Catherine Rampell observes that the number of new households is on the rise:
The pickup is probably related to job growth, which has enabled multigenerational households to spin off into multiple new homes. "We’re slowly but steadily improving, with more job opportunities in particular for younger households," [Chief economist at Moody's Analytics, Mark] Zandi said. "They can only live with their parents for so long. There are powerful centrifugal forces in those households, on both side. As soon as they have a chance to get out, many will take it."
Zandi notes that formation of a new household adds about $145,000 to the economy through a spending ripple effect.