Families headed by single parents were the lowest in the DC area, under 6%, as estimated by the Census Bureau for the years 2006–2008. For the same years, the percentage of people estimated to be living alone was the third highest in the DC area, at 45%. In 2009, Arlington was highest in the Washington DC Metropolitan area for the percentage of people who were single – 70.9%. 14.3% were married. 14.8% had families. In 2014 Arlington had the 2nd highest concentration of roommates after San Francisco among the 50 largest U.S. cities.