What Percentage of Americans Smoke Marijuana? January 31, 2020 In a July 2019 Gallup poll, 12% of U.S. adults said they smoke marijuana, a percentage that is essentially unchanged since 2015. CONT. Gallup Share: Share on X (Opens in new window) X Share on Facebook (Opens in new window) Facebook Share on Reddit (Opens in new window) Reddit Email a link to a friend (Opens in new window) Email Share on LinkedIn (Opens in new window) LinkedIn Share on Tumblr (Opens in new window) Tumblr Share on Pinterest (Opens in new window) Pinterest More Print (Opens in new window) Print