The drop is slight, but researchers say it's at least something. It dipped below 20 percent for the first time ever.
What's more, former smokers now outnumber current smokers, a trend that's been building for six years.
Still, experts say it's not all good news. More than 43 million adults are smokers and the vast majority of them smoke every day.
According to the new government report, smoking-related illnesses such as heart disease and lung cancer still claim more than 440,000 lives each year.
