The number of uninsured Americans increased by 3.4 million between 2004 and 2006, despite improving economic conditions. In the first four years of the decade, during a period of economic recession, the number increased by 6.0 million. The dominant factor in both periods was a decline in employer-sponsored insurance coverage. Although the recent decline was less than that experienced from 2000 to 2004, growth in public coverage was small, and the number of uninsured people increased by 1.0 million children and 2.4 million adults. Employer coverage declined most for self-employed or small-firm workers, in the South, and among noncitizens.