That number has skyrocketed by 7.5 million people since the pre-recession period in 2007. My first thought was the majority are young adults who cannot find work after college - but that only explains 1.2M of the 7.5M.
That leaves 6.3M in either the 18-24 range, or 35+. There have been a lot of anecdotal stories in the mainstream press the past few years of "middle age" adults moving back in with their parents (and even people not going through with divorces because they can't afford to), but this certainly is interesting data to help quantify it. [Apr 8, 2008: Recession Causes Relatives to Move in Together & Sharp Drop Off in Divorces] Of course if you are a mega bull, this is a lot of future household formation - once these folks can either get a job and/or a higher paying job that would allow them to move out (or back out) on their own. (as an aside this also apparently helped drop the official poverty rate.)
- Census says 69.2 million, or 30%, were doubled-up in 2011, up from 61.7 million adults, or 27.7%, in 2007.
- “These young adults who lived with their parents had an official poverty rate of only 8.4%, since the income of their entire family is compared with the poverty threshold,” David Johnson chief of the Housing and Household Economic Statistics Division at the U.S. Census Bureau said. “If their poverty status were determined by their own income, 45.3% would have had income falling below the poverty threshold for a single person under age 65.”
- Fewer households means fewer consumers for businesses desperate for demand. (You don’t need to buy a new TV if you can just use mom and dad’s.) At the same time, it continues to drag on a housing market that needs to burn off excess supply.