The availability and affordability of health insurance is a major policy concern in the U.S. About one-fifth of the U.S. population between the ages of 18 and 64 (36.3 million) lacks health insurance and the size of this population is expected to rise as health insurance becomes more costly relative to income for many people (DeNavas-Walt, Proctor, and Mills 2004; Rowland 2004). For most of the last decade, yearly job-based health insurance premium increases were higher than increases in both earnings and inflation (Gabel et al. 2001). If the premiums for health insurance continue to increase faster than personal income, recent estimates suggest that the percentage of uninsured workers could increase by more than 50 percent by 2009 (Gilmer and Kronick 2001).

The U.S. uninsured population is not homogenously distributed across Census regions, states, and communities. For example, 2001 uninsurance rates for the adult population under the age of 65 range from 10.4 percent in the New England region to 24.3 percent in the West South Central region, and from 8.7 percent in Iowa to 26 percent in Texas (Fronstin 2002). Cunningham and Ginsburg (2001) show that variation in uninsurance rates across 60 selected U.S. communities is high, ranging from a low of 4.7 percent in Rochester, NY to a high of 28.9 percent in Miami, FL.