About 21 percent of U.S. adults were smokers in 2009, about the same percentage as the year before, according to the Centers for Disease Control and Prevention. The smoking rate - which fell dramatically since the 1960s - has basically been flat since about 2004.
Teen smoking, at nearly 20 percent, has not been improving lately, either.
Health officials believe they've lost momentum because of cuts to anti-tobacco campaigns and shrewd marketing by cigarette companies.
The new report suggests that more than 46 million American adults still smoke cigarettes
"It's tragic," said CDC director Dr. Thomas Frieden, who calls smoking the No. 1 preventable cause of death in the United States. He estimates that smoking kills 1,000 Americans a day.
Some experts were particularly disheartened by a CDC finding in a second report that nearly all children who live with a smoker - 98 percent - have measurable tobacco toxins in their body.
Experts say tobacco taxes and smoking bans are driving down rates in some states. But nationwide, they say progress has been halted by tobacco company discounts or lack of funding for programs to discourage smoking or to help smokers quit.
The annual smoking report was based on government surveys. The second report looked at levels in the blood of cotinine, a chemical from tobacco smoke, in a total of more than 30,000 nonsmokers between 1999 and 2008.
Overall, detectable levels of cotinine dropped over the 10 years - from about 52 percent to 40 percent. That may be due in part to more smoking bans in workplaces, restaurants and other places.
But there were several bits of bad news in that report, too:
-Most of the decline came about 10 years ago.
-More than half of U.S. children ages 3 to 11 are exposed to secondhand smoke, and the CDC says there is no safe level of exposure.
-There's been virtually no improvement for children who live with a smoker, noted Matthew L. Myers, president of Campaign for Tobacco-Free Kids, a Washington-based research and advocacy organization.
Although the statistics are largely unchanged, advocates said the reports are important. They plan to use the data to pressure national, state and local governments to do more against smoking.
"Without bold action by our elected officials, too many lives, young and old, will suffer needlessly from chronic illness and burdensome health care expenses," Nancy Brown, chief executive of the American Heart Association, said in a statement.