In 1944, 41 percent of U.S. adults said they smoked; a number that held relatively steady over the next several decades.
At the start of the 1970s, four in 10 Americans still reported smoking, but by 1977, the rate had fallen to 36 percent. Twelve years later, in 1989, the smoking rate fell below the 30 percent mark for the first time.
In the late 2000s, smoking levels began to slowly drop again, when many cities and states started passing public smoking bans. In 2013, the percentage of Americans who smoked fell below 20 percent for the first time..
Smoking rates among those aged 18-29, have declined most dramatically since 2001. Over the past three years, 15 percent of adults aged 18-29 say they smoked a cigarette in the past week, compared with the 34 percent who said so in the early 2000s.
You can read the complete poll results here.