Where did all the people go?

The U.S. Census Bureau reported growth in the share of vacant homes, from 16.6 million units in third-quarter 2006 to 17.9 million in third-quarter 2007. Vacant homes accounted for 13.1 percent of the nation's estimated 126.2 million housing units in third-quarter 2006, compared to a 14 percent share of the nation's 128.2 million housing units in third-quarter 2007.

Empty homes are of special concern to home builders, who have been laboring to unload their unsold inventory during this housing slump.