Fewer Americans are smoking and those who are, light up less often than they used too.
In the mid-1960s, more than 40 percent of American adults smoked cigarettes, and more than half of all smokers smoked at least a pack a day, 20 cigarettes or more.
In the more than four decades since, those rates have declined dramatically. And University of California San Diego researcher John Pierce says heavy smoking rates dropped more in California than in other states.
"In 2007, the smoking prevalence in California was 11 percent, versus 18 percent in the rest of the country," he says. "And of that 11 percent, only 20 percent are pack-a-day smokers, versus 40 percent in the rest of the country. So that's sort of how the numbers pan out."
For the new study, researchers used nationwide surveys that asked a total of 1.8 million people over the years about their smoking habits.
Pierce says that after the 1964 Surgeon General's report, which warned of health risks associated with smoking, California moved more aggressively than other states to discourage smoking.
"California slapped on a big tax on cigarettes in 1967. Right from the get-go, they were aggressive in acting to disincentivize smoking."
Money raised by the tax, says Pierce, helped pay for other anti-smoking programs. About the same time, smoking bans started to limit the public places where people could smoke.
Pierce also shows that there are fewer heavy smokers in each new generation. Smokers typically hit their peak consumption in their 20s, and the data show that there are fewer heavy smokers among younger smokers today than in the past.
The decline in heavy smoking may have had a positive effect on the health of Californians. The state's lung cancer rate, which was once higher than the rest of the country, started going down in the 1980s. "Ever since," Pierce notes, "California's been dropping dramatically. They had a 30 percent decline in lung cancer. And it's about a 30 percent difference now with the rest of the country."