Homeownership rates, which peaked in 2004 at 69.2 percent and plunged in the wake of the housing bust, extended their decline in the first quarter of 2015, dropping to 63.7 percent, according to new U.S. Census Bureau data. That puts U.S. homeownership at levels last seen in the early late 1980s and early 1990s. As household formation has surged in recent months with more people moving out on their own, the rental vacancy rate also has fallen back to levels last seen in the early 1990s. That tightness in the rental market is why rent increases have been quite strong recently. During the first quarter, median U.S. rents hit $799, up 4.5 percent from the fourth quarter 2014. That’s the biggest quarter-on-quarter jump since 2006.