About 20 percent of adults in the U.S. were regular smokers last year, and the U.S. Centers for Disease Control and Prevention (CDC) is concerned that the numbers of adult smokers failed to decline significantly after a decade of near-steady progress against the nation’s top cause of preventable deaths.

Reuters reported Nov. 12 that the CDC analyzed data on more than 21,000 adults and found that cverall smoking prevalence was basically unchanged between 2007 and 2008. Researchers found that about 20.6 percent of American adults smoked — 79.8 percent daily, and 20.2 percent on most days.

The adult smoking rate fell 3.5 percent between 1998 and 2008, but most of the declines occurred prior to 2005. The CDC found that 45 percent of current smokers had attempted to quit at least once.

The findings appear in the Nov. 13, 2009 issue of the CDC’s Morbidity and Mortality Weekly Report.