Kicking the habit: Adult smoking rate in US is falling fast

Smoking is the nation's leading cause of preventable illness, causing more than 480,000 deaths each year in the United States, the CDC estimates.

The smoking rate's gradual decline has coincided with an increased public understanding that smoking is a cause of cancer, heart disease and other lethal health problems.

E-cigarettes heat liquid nicotine into a vapor, delivering the chemical that smokers crave without the harmful by-products generated from burning tobacco.

Some CDC surveys have shown a boom in e-cigarette use among teenagers, and health officials fear many of those kids will get hooked on nicotine and later become smokers.

Earlier this month, the Food and Drug Administration announced sweeping new rules that will for the first time apply long-standing rules covering traditional cigarettes to e-cigarettes, hookah tobacco, pipe tobacco and nicotine gels.