New York City's mayor has pledged to build (and preserve) that many units of affordable housing alone over the next 10 years [1]. About 80,000 of those will be new construction [2].

The broader picture is more vigorous. Developers applied to build 60% as much (over 50,000 units) in 2015 alone [3].

This is a political problem San Francisco has dug itself into.

[1] http://www1.nyc.gov/site/housing/index.page

[2] http://gothamist.com/2016/05/16/depends_on_what_affordable_m...

[3] https://www.buildingcongress.com/outlook/