Analysis #34 estimate sort-of natural affordable for rental stock

[maggiesu0725]

@lhendey ready for review

[lhendey]

@maggiesu0725 - i edited the code slightly - please review my changes. I'd like you to complete these table shells https://urbanorg.app.box.com/file/400004273763 - need to add across vacant and occupied. it's probably more straightforward to do that in SAS and then output the combined.