More adults have been moving in with their families or seeking out roommates instead of creating a home of their own, and the most obvious culprit is the difficult economy.
The number of shared households increased by 11.4 percent, to 22 million, between 2007 and 2010, the U.S. Census Bureau said in a report released Wednesday.
Shared households accounted for 18.7 percent of all U.S. households in 2010. That's up from 17 percent of all households in 2007, the Census Bureau said.
A shared household includes any adult who is not in school and has moved in with a family member or other adult that they aren't romantically involved with.
Census Bureau researchers said they didn't ask specifically why people were moving in with mom, dad or another roommate, but that the results suggest it was a way of coping with the weak economy.
That's what prompted Brad McGarr, now 26, to get a roommate.
McGarr graduated from high school in 2004, landed a good job in the Phoenix area and was soon settled into a nice apartment of his own.
Then he lost his job in 2009, and was financially devastated by a long stint of unemployment. He lived with family for a while and then landed a job as a technical support specialist in the Denver area. Between the high cost of living and the toll his unemployment stint took, he felt like he had no choice but to get a roommate.
McGarr said sharing the rent helped him to get back on his feet, financially. A few months ago, he moved out of the roommate situation and in with his girlfriend. He said it feels like he's restarting after the devastation of the recession.
"I think it's starting to get to the point where I'm having more of a normal adult life," he said.
Many people in their twenties and thirties are dealing with those kinds of setbacks.
Nearly half of the adults who moved into someone else's house between 2007 and 2010 were 25 to 34 years old, the Census researchers found. About 10 million people in that age were living in someone else's house in 2010, up from 8.5 million in 2007.
That's an age when people are typically starting out in their adult life, finding a place of their own or getting married and starting a family. Instead, economists say many are hobbled by the tight job market and student loan debt. Sharing a house is a symptom of those problems.
"People are living at home because either they're underemployed or they're unemployed, and that's because times are tough," said Patrick Newport, U.S. economist with IHS Global Insight.
Many people of that age appear to be moving back in with mom and dad. A separate report from Pew Research found that more than two in 10 people in that age range were living in a multigenerational household. Pew referred to them as the "boomerang generation" because they're coming back to the family home.
The fact that more people are sharing a home rather than striking out on their own is more bad news for the beleaguered housing market, which is still struggling from the effect of the massive housing bust. Newport expects it to have a ripple effect on the housing sector for quite some time.
Still, he said some of the money people aren't spending on housing is likely being diverted to other parts of the economy, if they are drawing a paycheck at all.
"Instead of spending their money on rent or on a mortgage, they'll buy computers or they'll pay off their bills," he said.