Rental build rate by affordability level

Per 1000 units of housing stock. Rent is expressed as a multiple of local median rent.

1950s rental build rate was 7 per 1000 units, 1970s was 9 per 1000 units; since 1990s it is under 4.5 per 1000 units.
New buildings are those 2-10 years old (buildings less than two years old are excluded in order to avoid capturing concessionary rates). "Local" means in the same Public Use Microdata Area for 1960 and 1990+, or in the same IPUMS county group for 1970 and 1980. Rate is calculated as the number of rental units built in the past 10 years divided by the total housing stock of 10 years previous.
Chart: Brandon Istenes / Rent & RentierSource: US Census / ACSCreated with Datawrapper