The percentage of American adults who smoke cigarettes has held in a range of 20 to 21 percent since 2005, as the decline in smoking has stalled, according to government figures released Tuesday.
The figures from the Centers for Disease Control showed the number of adult smokers dropped between 2000 and 2005, but the percentage of adult smokers has remained at about 20-21 percent since 2005.
In 2009, nearly 24 percent of men smoked, compared with 18 percent of women. About 31 percent of those living below the poverty line smoked, the government agency said.
"Smoking is still the leading preventable cause of death in this country," said CDC director Thomas Frieden.
"But progress is possible. Strong state laws that protect non-smokers from second-hand smoke, higher cigarette prices, aggressive ad campaigns that show the human impact of smoking and well-funded tobacco control programs decrease the number of adult smokers and save lives."
The CDC said passive or secondhand smoke remains a problem for non-smokers including many children.
It said 54 percent of children between the ages of three and 11 years old were exposed to second-hand smoke, and nearly all children who live with a smoker have measurable levels of toxic chemicals from cigarette smoke.
The figures show prevalence of smoking declines with education. Fewer than six percent of adults with a graduate degree smoke compared to more than 25 percent of adults with no high school diploma.