dfabulich / baseline-calculator

A script to estimate how long it takes new web features to achieve widespread availability
ISC License
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Baseline Calculator: How long until I can use?

How long does it take for web features to achieve widespread availability?

tl;dr: 63 features became eligible for Baseline in 2020. 95% of those features achieved 95% market share in 31 months.

Background: How should "Baseline" be defined?

Web Platform Baseline is designed to provide clear information about which web platform features are safe to use in your projects today.

Features become part of Baseline when they are supported in the current and previous version of all major browsers—Chrome, Edge, Firefox, and Safari.

Since then, we've been discussing at https://github.com/web-platform-dx/feature-set/issues/174 whether 2 major versions is long enough to wait.

Part of that discussion has been to ask whether we should wait for more versions (how many?) and how we should define a "major" version.

But we've also considered whether instead to wait a certain amount of time to consider a feature as part of Baseline, or to wait for a certain threshold of market share instead.

Can we define Baseline based on market share instead?

caniuse.com provides a convenient report on browser version market share. For example, in May 2023, https://caniuse.com/dialog shows that only 94% of users can use the new <dialog> element, even though it's available in Safari 15.6 and up since July 2022. (When I launched a feature using <dialog> in March, I got a lot of complaints.)

But there are problems with defining "Baseline" based on market share like this:

Can we define Baseline based on time instead?

It would be easy to define Baseline by saying that a feature is in Baseline two years after the feature is supported in all major browsers.

That's a simple, objectively verifiable definition. The problem is: is two years the right amount of time? Should it be four years? One year? Six months?

This repository is intended to answer that question:

How many months/years does it take for a feature to reach widespread availability?

Methodology

Data Source: Caniuse and StatCounter

Caniuse.com makes its data available via Github under a CC-BY-4.0 license. https://github.com/fyrd/caniuse The data is in data.json. (Browser release dates are in data-2.0.json, but data.json has a longer git history.) We're very grateful to have access to this treasure trove of data.

Caniuse data pulls its market-share data from StatCounter.

"Keystone" Release Date: The date a feature first became available in all major browsers

As features become available in all major browsers, one browser goes first, then another goes second, until eventually the last major browser supports it.

We'll call that last major browser to support the feature the "keystone browser." (In a curved stone archway, the "keystone" is the one at the very center of the top. The keystone is added last, and holds all of the other stones together.)

The "keystone version" is the version that makes its browser the keystone, and the "keystone release date" is the release date of the keystone version.

For example, the CSS revert value feature was first available in Safari 9.1 in 2016, then in Firefox 67 in 2019, then Chrome 84 on July 14, 2020, then in Edge 84 on July 16, 2020.

So, in this example, Edge was the "keystone browser" for the feature; Edge 84 was the "keystone version," and the "keystone release date" was July 16, 2020.

This repository includes a Node script, compute-keystone-release-dates.mjs, which generated keystone-release-dates.json, which is also checked in.

compute-keystone-release-dates.mjs uses the feature data from Caniuse's data-2.0.json, finds all of the features that are currently available in all major browsers, then computes the keystone release date for those features, generating keystone-release-dates.json.

Historical Market Share

We gather historical market share data from the Git history of the Caniuse data.json file.

compute-historical-share.mjs pulls the git log of data.json, then uses git checkout to view it at every commit in its history. We track the timestamp of the commit and the market share of each feature in the commit in historical-feature-data.json.

There's a catch: StatCounter/Caniuse doesn't track Android Chrome versions

https://gs.statcounter.com/browser-version-market-share

StatCounter lists all Android Chrome as "Chrome for Android," without breaking it down by version at all. You'll see that caniuse.com lists all Chrome Android traffic as coming from the latest release version of Chrome, v113. There's a filed issue about this, here: https://github.com/Fyrd/caniuse/issues/3518

We know for sure that Chrome 113 doesn't have 100% of Android Chrome market share, because if you're on Android 6 (2015) or below, you can't upgrade to the latest version of Google Chrome. https://en.wikipedia.org/wiki/Template:Google_Chrome_release_compatibility

StatCounter does provide an Android Version Market Share report. https://gs.statcounter.com/android-version-market-share/ (Note that this report is about Android OS versions, not browser versions.)

In May 2023, Android 6 is 1.67% of Android traffic, and "Other" is about 3% more. StatCounter says that Chrome for Android is around 40% of global traffic; if we assume that 5% of those 40 points are on very old versions of Android, then roughly 2% of global traffic is falsely reported as belonging to the latest version of Google Chrome, when, in fact, they're on older versions.

But we do have a partial mitigation: although the current HEAD revision of caniuse data.json does not include accurate historical data about Android Chrome, we're measuring historical data by checking out old revisions of data.json, and those old revisions are accurate about the then-current version of Android Chrome as it was at the time. (But they were wrong even then about then-obsolete versions of Chrome.)

I don't think that this will fundamentally alter the final results, but, if we're concerned about it, we could try to investigate another data source, e.g. Akamai's RUM Archive. https://github.com/rum-archive/rum-archive

And another catch: Caniuse lists a huge amount of unknown-browser "Other" traffic ("dark matter"), so we'll just factor that out

When you sum the marketshare of all of the browsers in caniuse's data set, it doesn't add up to 100%. It's not even supposed to add up to 100%, because StatCounter doesn't track all browsers; it lumps unknown browsers into a mysterious "Other" category.

As of Aug 2023, all of caniuse's browsers add up to 97.78%, leaving 2.22% share unknown. Caniuse's approach is to be pessimistic about the unknown share, assuming that no features work in the unknown browsers.

So, for example, https://caniuse.com/inline-block, which was available in all browsers in 2009, and works in all browsers and browser versions that caniuse tracks, is currently only at 97.78% global marketshare according to caniuse, because of that 2.22% unknown "dark matter" traffic. It is simply impossible for inline-block to reach 98% share on caniuse.

Here, we're going to compensate for dark matter, by computing the total share of all tracked browsers (97.78%), and dividing all of caniuse's marketshare numbers by that amount, the "dark matter factor". For example, inline-block has 100% share in our analysis. To pick another example, we'll say that https://caniuse.com/es6-module, which caniuse says has 94.92% share, actually has 94.92% / 0.9778 = 97.07% share.

We'll call this number the "tracked marketshare" for the feature, in contrast with caniuse's number.

And we calculate this "dark matter factor" at each point in history. For example, in Jan 2019, the dark matter factor was 95.90%, so, when we're assessing the tracked marketshare of a feature in Jan 2019, we'll divide its caniuse Jan 2019 marketshare by 95.90%.

Target Dates

Using keystone-release-dates.json and historical-feature-data.json, we can compute the dates at which each feature reached certain marketshare targets. We do this with a compute-target-dates.mjs script.

We start by considering only the web features that are supported by all major browsers. I'm calling those features "Baselineable" features. Baselineable features could become part of Baseline, but only if/when they achieve "enough" market share. (As of Aug 2023, there are 177 Baselineable features, supported in the current latest versions of all major browsers.)

We compute the following dates for each Baselineable feature:

If the feature has not yet reached that level of marketshare, we leave it null.

The output is a target-dates.json file, which looks like this:

{
  "abortcontroller": {
    "keystone": "2019-04-02",
    "marketshare": 97.01,
    "reached": {
      "80": "2018-11-06",
      "85": "2019-07-08",
      "90": "2020-03-05",
      "91": "2020-05-08",
      "92": "2020-08-11",
      "93": "2021-02-05",
      "94": "2021-11-04",
      "95": "2022-07-03",
      "96": "2022-11-04",
      "97": "2023-06-03",
      "98": null,
      "99": null
    }
  },
}

compute-target-dates.mjs also generates a survival-input-data.csv file, which you can open in any spreadsheet. You can sort/filter the features by any column, just to get a feel for the data.

Baseline Calculator

baseline-calculator.mjs does the work here, based on target-dates.json.

For example, let's just look at the features launched in 2019. Here they all are, based on survival-input-data.csv.

feature indeterminate-checkbox brotli flac download pointer rellist date-tolocaledatestring abortcontroller
marketshare 98.57 97.41 97.38 97.57 97.23 97.53 96.93 97
days to 80% 0 0 0 0 37 0 35 0
days to 85% 0 0 0 46 99 63 156 97
days to 90% 0 0 0 76 193 276 338 338
days to 91% 0 0 203 76 374 338 402 402
days to 92% 164 0 203 138 434 379 521 497
days to 93% 224 76 203 138 480 472 856 675
days to 94% 316 138 232 209 647 583 947 947
days to 95% 346 413 505 505 953 976 1188 1188
days to 96% 558 869 869 654 1057 1266 1347 1312
days to 97% 955 1353 1353 1018 1314 1523 not yet 1523
days to 98% 1274 not yet not yet not yet not yet not yet not yet not yet
days to 99% not yet not yet not yet not yet not yet not yet not yet not yet

Our goal is to perform a survival analysis. For the table above, we can ask questions like this, which you can answer just by looking at the table above:

For each question, we ask about a target marketshare (e.g. 95% share) and a percentile of Baselineable features that have reached the target marketshare (e.g. 50% of features).

For the eight features of 2019, listed above, we can build a table of these questions and answers, like this:

Market Share 50% of features 75% of features 80% of features 90% of features 95% of features 97% of features 98% of features 99% of features 100% of features
80% share 0 months 0 months 1 months 1 months 1 months 1 months 1 months 1 months 1 months
85% share 2 months 3 months 3 months 5 months 5 months 5 months 5 months 5 months 5 months
90% share 3 months 9 months 11 months 11 months 11 months 11 months 11 months 11 months 11 months
91% share 7 months 12 months 13 months 13 months 13 months 13 months 13 months 13 months 13 months
92% share 7 months 14 months 17 months 17 months 17 months 17 months 17 months 17 months 17 months
93% share 7 months 16 months 23 months 29 months 29 months 29 months 29 months 29 months 29 months
94% share 11 months 22 months 32 months 32 months 32 months 32 months 32 months 32 months 32 months
95% share 17 months 33 months 40 months 40 months 40 months 40 months 40 months 40 months 40 months
96% share 29 months 42 months 44 months 45 months 45 months 45 months 45 months 45 months 45 months
97% share 45 months 51 months 51 months not yet not yet not yet not yet not yet not yet
98% share not yet not yet not yet not yet not yet not yet not yet not yet not yet
99% share not yet not yet not yet not yet not yet not yet not yet not yet not yet

That's what the Baseline calculator does, either for all features for all time, or just for a specified calendar year.

Reproducing Results

Submodules

We gather data from caniuse via a Github submodule. The first step is to populate the submodule, like this:

git submodule update --init --recursive

(You can skip this step if you just want to run baseline-calculator.mjs.)

Generating data

  1. Run compute-keystone-release-dates.mjs to generate keystone-release-dates.json
  2. Run compute-historical-share.mjs to generate historical-feature-data.json.
  3. Run compute-target-dates.mjs to generate target-data.json and survival-input-data.csv
  4. Run baseline-calculator.mjs to generate the result table

Interpretation of Results

Here are the results of running baseline-calculator.mjs on all features for all time.

Market Share 50% of features 75% of features 80% of features 90% of features 95% of features 97% of features 98% of features 99% of features 100% of features
80% share 0 months 1 months 2 months 6 months 14 months 15 months 17 months 17 months 43 months
85% share 0 months 3 months 3 months 10 months 16 months 17 months 20 months 43 months not yet
90% share 3 months 9 months 11 months 18 months 35 months not yet not yet not yet not yet
91% share 5 months 12 months 16 months 23 months 44 months not yet not yet not yet not yet
92% share 7 months 16 months 20 months 28 months not yet not yet not yet not yet not yet
93% share 9 months 21 months 24 months 32 months not yet not yet not yet not yet not yet
94% share 17 months 28 months 29 months 43 months not yet not yet not yet not yet not yet
95% share 22 months 34 months 37 months not yet not yet not yet not yet not yet not yet
96% share 33 months 45 months 51 months not yet not yet not yet not yet not yet not yet
97% share 44 months not yet not yet not yet not yet not yet not yet not yet not yet
98% share not yet not yet not yet not yet not yet not yet not yet not yet not yet
99% share not yet not yet not yet not yet not yet not yet not yet not yet not yet

You'll notice a lot of "not yets" on this table.

Looking at the cell near the upper right (85% share, 100% of features), the table is saying that some features supported in all browsers haven't reached 85% share yet. (It's actually just one feature, css-media-range-syntax, shipped as part of iOS 16.4 in March 2023.)

Looking at the cell in the lower left (99% share, 50% of features), the table is saying that more than half of Baselineable features have never achieved 99% market share. In fact, only 12 of the 177 Baselineable features have achieved 99% market share; only 54 have achieved 98% market share.

That's because 98% market share is a surprisingly high bar to achieve. If you insist on avoiding web features that haven't achieved 98% market share, you'll be missing out on features that shipped years ago.

Just to pick a few examples, none of these features have reached 98% market share:

All of these features became supported in all major browsers more than five years ago.

Why does it take so long to achieve 98% market share? There are a few reasons:

Cohort Analysis

baseline-calculator.mjs also accepts a command-line argument, allowing you to specify a "cohort year." For example, --cohort=2016 will consider all/only features whose keystone release date was in 2016. (It works by string comparison, so you can even pass a cohort month if you want, like this: --cohort-2016-08)

How does it look?

Cohorts by year for seven years

Here are the cohorts: # 2016: 17 features Features: array-find-index, array-includes, arrow-functions, background-position-x-y, background-repeat-round-space, border-radius, comparedocumentposition, document-scrollingelement, es6-class, es6-generators, font-feature, insert-adjacent, internationalization, localecompare, pagevisibility, proxy, rest-parameters Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|6 months|14 months|14 months|17 months|43 months|43 months|43 months|43 months|43 months 85% share|11 months|14 months|14 months|17 months|43 months|43 months|43 months|43 months|43 months 90% share|18 months|20 months|22 months|26 months|43 months|43 months|43 months|43 months|43 months 91% share|23 months|23 months|24 months|27 months|43 months|43 months|43 months|43 months|43 months 92% share|27 months|28 months|28 months|30 months|43 months|43 months|43 months|43 months|43 months 93% share|31 months|32 months|32 months|35 months|43 months|43 months|43 months|43 months|43 months 94% share|35 months|36 months|36 months|37 months|43 months|43 months|43 months|43 months|43 months 95% share|35 months|38 months|39 months|42 months|43 months|43 months|43 months|43 months|43 months 96% share|36 months|47 months|47 months|47 months|50 months|50 months|50 months|50 months|50 months 97% share|41 months|70 months|72 months|79 months|79 months|79 months|79 months|79 months|79 months 98% share|70 months|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2017: 28 features Features: array-find, async-functions, bloburls, const, css-font-stretch, css-grid, css-variables, css-writing-mode, element-closest, fetch, focusin-focusout-events, form-attribute, form-validation, gamepad, input-pattern, keyboardevent-getmodifierstate, let, matchesselector, meter, object-entries, object-values, once-event-listener, outline, passive-event-listener, svg-css, template, user-timing, viewport-units Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|0 months|3 months|4 months|7 months|17 months|17 months|17 months|17 months|17 months 85% share|2 months|5 months|10 months|17 months|17 months|34 months|34 months|34 months|34 months 90% share|5 months|14 months|15 months|17 months|17 months|44 months|44 months|44 months|44 months 91% share|5 months|18 months|20 months|20 months|21 months|44 months|44 months|44 months|44 months 92% share|15 months|22 months|22 months|23 months|24 months|44 months|44 months|44 months|44 months 93% share|20 months|25 months|26 months|28 months|28 months|44 months|44 months|44 months|44 months 94% share|26 months|29 months|29 months|30 months|32 months|44 months|44 months|44 months|44 months 95% share|28 months|34 months|34 months|37 months|40 months|44 months|44 months|44 months|44 months 96% share|35 months|44 months|49 months|52 months|57 months|57 months|57 months|57 months|57 months 97% share|53 months|68 months|68 months|69 months|69 months|69 months|69 months|69 months|69 months 98% share|75 months|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2018: 22 features Features: beacon, constraint-validation, css-media-interaction, dom-manip-convenience, eme, font-unicode-range, input-minlength, kerning-pairs-ligatures, link-icon-png, pad-start-end, promise-finally, resource-timing, serviceworkers, subresource-integrity, svg-fragment, svg-html5, transforms2d, upgradeinsecurerequests, urlsearchparams, wasm, woff2, wordwrap Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|0 months|0 months|1 months|4 months|8 months|10 months|10 months|10 months|10 months 85% share|0 months|2 months|6 months|8 months|9 months|20 months|20 months|20 months|20 months 90% share|6 months|10 months|14 months|19 months|20 months|35 months|35 months|35 months|35 months 91% share|10 months|14 months|14 months|20 months|21 months|35 months|35 months|35 months|35 months 92% share|13 months|14 months|16 months|20 months|23 months|35 months|35 months|35 months|35 months 93% share|14 months|18 months|19 months|23 months|27 months|35 months|35 months|35 months|35 months 94% share|20 months|21 months|22 months|27 months|35 months|39 months|39 months|39 months|39 months 95% share|23 months|27 months|31 months|35 months|40 months|50 months|50 months|50 months|50 months 96% share|35 months|43 months|43 months|51 months|51 months|52 months|52 months|52 months|52 months 97% share|54 months|61 months|62 months|62 months|62 months|62 months|62 months|62 months|62 months 98% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2019: 8 features Features: abortcontroller, brotli, date-tolocaledatestring, download, flac, indeterminate-checkbox, pointer, rellist Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|0 months|0 months|1 months|1 months|1 months|1 months|1 months|1 months|1 months 85% share|2 months|3 months|3 months|5 months|5 months|5 months|5 months|5 months|5 months 90% share|3 months|9 months|11 months|11 months|11 months|11 months|11 months|11 months|11 months 91% share|7 months|12 months|13 months|13 months|13 months|13 months|13 months|13 months|13 months 92% share|7 months|14 months|17 months|17 months|17 months|17 months|17 months|17 months|17 months 93% share|7 months|16 months|23 months|29 months|29 months|29 months|29 months|29 months|29 months 94% share|11 months|22 months|32 months|32 months|32 months|32 months|32 months|32 months|32 months 95% share|17 months|33 months|40 months|40 months|40 months|40 months|40 months|40 months|40 months 96% share|29 months|42 months|44 months|45 months|45 months|45 months|45 months|45 months|45 months 97% share|45 months|51 months|51 months|not yet|not yet|not yet|not yet|not yet|not yet 98% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2020: 63 features Features: apng, array-flat, bigint, chacha20-poly1305, contentsecuritypolicy2, cryptography, css-all, css-any-link, css-backgroundblendmode, css-caret-color, css-case-insensitive, css-conic-gradients, css-default-pseudo, css-env-function, css-filters, css-focus-within, css-font-rendering-controls, css-in-out-of-range, css-indeterminate-pseudo, css-math-functions, css-placeholder, css-placeholder-shown, css-read-only-write, css-rrggbbaa, css-shapes, css-snappoints, css-supports-api, css-text-orientation, css-textshadow, datauri, details, es6-module, es6-module-dynamic-import, eventsource, fileapi, flow-root, font-kerning, font-loading, font-variant-numeric, getboundingclientrect, iframe-srcdoc, indexeddb, indexeddb2, intl-pluralrules, justify-content-space-evenly, keyboardevent-key, link-rel-preconnect, object-fit, ol-reversed, path2d, prefers-color-scheme, prefers-reduced-motion, rel-noopener, resizeobserver, shadowdomv1, svg, svg-smil, textencoder, tls1-3, unhandledrejection, vector-effect, webgl, will-change **Note: In January 2020, Microsoft release Edge 79, switching its browser engine to Chromium. That made Edge 79 the keystone browser for dozens of features, way more than usual.** Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|0 months|0 months|0 months|1 months|2 months|6 months|6 months|16 months|16 months 85% share|0 months|0 months|0 months|2 months|3 months|16 months|16 months|16 months|16 months 90% share|0 months|4 months|6 months|9 months|10 months|16 months|16 months|16 months|16 months 91% share|0 months|7 months|7 months|11 months|13 months|16 months|16 months|18 months|18 months 92% share|2 months|9 months|10 months|15 months|16 months|16 months|16 months|22 months|22 months 93% share|2 months|13 months|15 months|19 months|20 months|24 months|24 months|27 months|27 months 94% share|7 months|21 months|22 months|25 months|27 months|29 months|29 months|40 months|40 months 95% share|9 months|30 months|30 months|30 months|31 months|36 months|36 months|41 months|41 months 96% share|21 months|33 months|33 months|41 months|41 months|44 months|44 months|not yet|not yet 97% share|41 months|41 months|not yet|not yet|not yet|not yet|not yet|not yet|not yet 98% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2021: 14 features Features: audio-api, css-image-orientation, css-logical-props, css-matches-pseudo, css-not-sel-list, css-revert-value, css-sticky, css3-tabsize, element-scroll-methods, flexbox-gap, font-family-system-ui, link-rel-preload, mediarecorder, webgl2 Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|0 months|1 months|2 months|2 months|2 months|2 months|2 months|2 months|2 months 85% share|0 months|2 months|2 months|3 months|4 months|4 months|4 months|4 months|4 months 90% share|2 months|4 months|5 months|7 months|9 months|9 months|9 months|9 months|9 months 91% share|3 months|6 months|9 months|10 months|14 months|14 months|14 months|14 months|14 months 92% share|5 months|10 months|13 months|14 months|21 months|21 months|21 months|21 months|21 months 93% share|9 months|14 months|20 months|21 months|22 months|22 months|22 months|22 months|22 months 94% share|15 months|18 months|22 months|26 months|not yet|not yet|not yet|not yet|not yet 95% share|22 months|26 months|not yet|not yet|not yet|not yet|not yet|not yet|not yet 96% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 97% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 98% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2022: 17 features Features: border-image, broadcastchannel, css-cascade-layers, css-containment, css-focus-visible, css-font-palette, css-gradients, css-media-resolution, css-motion-paths, css-overflow, css-overscroll-behavior, css-text-align-last, dialog, permissions-api, text-emphasis, transforms3d, webp Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|1 months|1 months|2 months|2 months|2 months|2 months|2 months|2 months|2 months 85% share|3 months|3 months|3 months|3 months|5 months|5 months|5 months|5 months|5 months 90% share|5 months|6 months|6 months|8 months|9 months|9 months|9 months|9 months|9 months 91% share|6 months|7 months|7 months|10 months|not yet|not yet|not yet|not yet|not yet 92% share|8 months|9 months|10 months|not yet|not yet|not yet|not yet|not yet|not yet 93% share|9 months|11 months|not yet|not yet|not yet|not yet|not yet|not yet|not yet 94% share|15 months|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 95% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 96% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 97% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 98% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet # 2023: 8 features Features: colr, css-container-queries, css-container-query-units, css-media-range-syntax, import-maps, js-regexp-lookbehind, screen-orientation, viewport-unit-variants Market Share|50% of features|75% of features|80% of features|90% of features|95% of features|97% of features|98% of features|99% of features|100% of features ---|---|---|---|---|---|---|---|---|--- 80% share|0 months|2 months|2 months|2 months|2 months|2 months|2 months|2 months|2 months 85% share|1 months|2 months|3 months|not yet|not yet|not yet|not yet|not yet|not yet 90% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 91% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 92% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 93% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 94% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 95% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 96% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 97% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 98% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet 99% share|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet|not yet

That's a lot of tables, so, here's just the "95% features" column, by cohort year:

Market Share 80% share 85% share 90% share 91% share 92% share 93% share 94% share 95% share 96% share 97% share
2016 43 months 43 months 43 months 43 months 43 months 43 months 43 months 43 months 50 months 79 months
2017 17 months 17 months 17 months 21 months 24 months 28 months 32 months 40 months 57 months 69 months
2018 8 months 9 months 20 months 21 months 23 months 27 months 35 months 40 months 51 months 62 months
2019 1 months 5 months 11 months 13 months 17 months 29 months 32 months 40 months 45 months not yet
2020 2 months 3 months 10 months 13 months 16 months 20 months 27 months 31 months 41 months not yet
2021 2 months 4 months 9 months 14 months 21 months 22 months not yet not yet not yet not yet
2022 2 months 5 months 9 months not yet not yet not yet not yet not yet not yet not yet
2023 2 months not yet not yet not yet not yet not yet not yet not yet not yet not yet

Interpretation of Cohort Analysis: It's improving!

Every column shows improvement over time. Next year, we might find that the 2021 cohort has an even better result.

Conclusion: Baseline can and should be time-based