Data were analyzed by age group (18-44, 45-64, and ≥65 years), sex, race/ethnicity (white, black, Hispanic, Asian/Pacific Islander, and American Indian/Alaskan Native†), and education (less than high school diploma, high school diploma, some college, college degree or higher). All reported percentages were age-standardized using the 2000 U.S. standard projected population, distribution no. 8,6 except for age groups, for which age-specific percentages were reported. Linear trends across survey periods were assessed using orthogonal polynomial coefficients, and results with a p-value <0.05 were considered significant. The total number of respondents ranged from 356,112 in 2005 to 432,607 in 2009. State-specific (including the District of Columbia [DC]) sample sizes ranged from 2,432 (Alaska, 2009) to 39,549 (Florida, 2007).