During the last 10 years, a surge in renters throughout the nation has been driving rates up. Home ownership has dipped to 1967 levels. Only 63.5 percent of American households now own homes compared with 69 percent near the peak of the housing bubble. In Cook County, 43.7 percent of households were renters in 2014, according to the most recent data from the Institute for Housing Studies at DePaul University. That compares with the pre-housing crisis level of 37.7 percent in 2007.