America’s Families and Living Arrangements: 2007 – Population Characteristics, September 2009 – “This report presents basic trends in household and family composition and living arrangements. Previous U.S. Census Bureau reports in this series were based only on the Annual Social and Economic supplement to the Current Population Survey (CPS ASEC). With the full implementation of the American Community Survey (ACS) and due to its large sample size, there now exist annual data to examine household and family characteristics for geographic areas below the national level (3 million addresses). While the CPS contains detailed information about family structure and characteristics over time, the ACS provides information about how basic family and household characteristics vary across geographic areas, such as states and counties.”