The number of chain smokers across the country has taken -- a dip.
A study by researchers at the University of California, San Diego shows that the number of heavy smokers, people who smoke a pack a day or more, has declined dramatically over the past 40 years. From 1965, scientists say the number dropped into the single digits.
In California, the number was five points lower than the rest of the nation.
"It went from over a quarter of the population to just two percent in 2007," said John Pierce, Ph.D., a researcher at UCSD.
In 2007, only about seven percent of smokers nationwide went through at least a pack of cigarettes a day, also down from 25 percent in the 1960's.
Researchers attribute the decline, in part, to higher cigarette taxes. They also found that younger generations of smokers are changing their smoking habits.
"A lot of this drop in pack a day smoking, has come from young people never reaching the level of even half a pack a day," Pierce explained.
However, that trend may be changing. Last year, researchers at the University of Michigan found that the decline in teen smoking has plateaued. Their research found that younger teens may be lighting up more often.
According to the Centers for Disease Control, about 21 percent of adults in this country are smokers.