fix: ZeroDivision Error

[doneachh]

Closes # (if applicable).

Changes proposed in this Pull Request

implemented division through zero check

Checklist

• [ ] I tested my contribution locally and it seems to work fine.
• [ ] Code and workflow changes are sufficiently documented.
• [ ] Newly introduced dependencies are added to envs/environment.yaml and envs/environment.docs.yaml.
• [ ] Changes in configuration options are added in all of config.default.yaml, config.tutorial.yaml, and test/config.test1.yaml.
• [ ] Changes in configuration options are also documented in doc/configtables/*.csv and line references are adjusted in doc/configuration.rst and doc/tutorial.rst.
• [ ] A note for the release notes doc/release_notes.rst is amended in the format of previous release notes, including reference to the requested PR.

[doneachh]

Hi @davide-f ! :) Can you please review my bugfix here? The error appears if there is data missing in the unsd data. As there is no data, we assume it to be 0 --> In the division we get the ZeroDivision Error.