Studies of ex-smokers show that their risk of dying from -related disease decreases with each year of non . Encouraged by such evidence, more than 40 million people in the U.S. quit in the year following the 1964 surgeon general's report. The proportion of males who smoke decreased from more than 60 percent to about 25 percent; however, the percentage of women who smoke cigarettes increased. Smoking also became more prevalent among young adults, with about 29 percent of high school seniors admitting to smoking in 1975; but by 1987 this propor ....