US health officials said the percentage of Americans who are smokers has fallen to the lowest level since 1965, when they began keeping records.
The Centers for Disease Control and Prevention (CDC) said the number of American adults smokers fell from 45.1 million in 2005, or 20.9 percent of the USA population at the time, to 42.1 million.
Despite progress in reducing the overall number of US smokers, rates remained on the high side for some groups, particularly lower-income people, as well as gays and lesbians, the CDC said.
Smoking accounts for one in five US deaths annually, taking more than 480,000 lives.
According to US government data, smoking costs the economy more than $289 billion a year for medical care and lost productivity.