Delighted federal health officials said Thursday the number of smokers has plummeted by nearly 20 percent in the past 10 years and dropped a full percentage point in the last year alone.
They're not sure of all the reasons why, but credit anti-smoking campaigns, better insurance coverage to help people kick the habit, and tougher laws that make it harder to smoke in a growing number places.
But the researchers note that people covered by Medicaid — the government health insurance plan for low-income people, and those who don't have any health insurance at all are far more likely to smoke than people with good health insurance.
"The percentage of U.S. adults who smoke cigarettes declined from 20.9 percent in 2005 to 16.8 percent in 2014," the Centers for Disease Control and Prevention team wrote in their report.
"Cigarette smoking was significantly lower in 2014 (16.8 percent) than in 2013 (17.8 percent)."
The CDC team used an annual survey of Americans for their findings.
One troubling finding: adults who are uninsured or on Medicaid smoke at rates more than double those for adults with private health insurance or Medicare.
"Data from the 2014 National Health Interview Survey show that 27.9 percent of uninsured adults and 29.1 percent of Medicaid recipients currently smoke," the researchers wrote. "By contrast, 12.9 percent of adults with private insurance and 12.5 percent of those on Medicare currently smoke."
Men are more likely to smoke than women - 18.8 percent versus 14.8 percent. People over 65 are the least likely to smoke - just 8.5 percent of them do.
"Smoking kills half a million Americans each year and costs more than $300 billion," CDC director Dr. Tom Frieden said in a statement.
"This report shows real progress helping American smokers quit and that more progress is possible."
Last year, smoking rates hit a 50-year low. Now they're even lower.
"Our tremendous progress shows that we know how to win the fight against tobacco. Proven solutions must be fully implemented across the nation, including higher tobacco taxes, strong smoke-free laws, well-funded tobacco prevention and cessation programs that include mass media campaigns, and comprehensive, barrier-free health insurance coverage for smoking cessation treatments," said Matthew Myers, president of the Campaign for Tobacco-Free Kids.
"After stalling in the mid-2000s, adult and youth smoking rates began declining again after the federal cigarette tax was increased by 62 cents in 2009. Significant additional increases in federal and state cigarette taxes can further drive down smoking rates," Myers added.
The researchers say it's not clear if products such as e-cigarettes are helping people quit. So far, there's little evidence that they are.
Separately, the Department of Housing and Urban Development announced a proposed rule that would force public housing agencies to limit smoking in developments.It would ban smoking in publicly funded apartments or houses, offices and outdoor areas in those developments.
"In addition to protecting non-smokers, smoke-free public housing policies would encourage smokers living in affected properties to quit smoking," said Chris Hansen, president of the American Cancer Society Cancer Action Network.
The American Lung Association and American Academy of Pediatrics praised the move, too.
"A February 2015 CDC study found that two in five children living in federally subsidized housing overall are exposed to secondhand smoke. Even more troubling is that seven in ten African-American children are exposed to secondhand smoke in their homes," the groups said in a joint statement.