Even during the homebuying boom, the share of U.S. households living in rental housing never fell below 30%, according to America's Rental Housing: Meeting Challenges, Building on Opportunities, a report on the state of the rental housing industry from Harvard University’s Joint Center for Housing Studies (JCHS). 

America's Rental Housing: Meeting Challenges, Building on Opportunities includes extensive data on the apartment industry in the key areas of: market conditions; renter demographics; and the rental housing stock.  Among the report’s key findings:

• Rental housing serves a large and diverse population of nearly 39 million U.S. households. 
  
  
• The number of renter households grew by almost four million between 2005 and 2010. 
  
  
• Population trends should lift the number of renter households by more than 3.6 million between 2010 and 2020.
  
  
• Renters cover the age spectrum.  While younger groups are much more likely to rent their housing, more heads of renter households are between the ages of 35 and 64 (46%) than under 35 (41%).
  
  
• Single-person households make up nearly two out of every five renters.  The rest of the renter population is fairly equally divided among married couples with and without children, single-parent households, and other related and unrelated groups of people.
  
  
• Minority households contributed 81% of the renter growth from 2001 to 2010.  Hispanics accounted for 39% and blacks for 27% of the increase.  Over the last decade, the minority share of renters rose from 39% to 45%.
  
  
• Rental housing starts (single-family and multifamily) averaged approximately 300,000 units annually from 1995–2004.  They fell to about 230,000 units a year in 2005–2008 and then to just over 100,000 in 2009.
  
  
• The financial crisis severely curtailed multifamily lending.  The only net additions to outstanding multifamily debt since 2008 have come from Fannie Mae, Freddie Mac and the FHA, while the volume for all other financing sources combined dropped by $40 billion.
  
  
• The overall vacancy rate hit 10.7% at the end of 2009, up from 9.6% at the end of 2007.
  
  
• Real contract rents have climbed by more than 15% since 1980.
  
  
• The majority of the nation’s low-cost building stock is unassisted.