In a new poll from Gallup, 45 percent of U.S. adults said they had tried marijuana at least once in their lives. This year, 12 percent of American said they currently smoke marijuana, up from 7 percent in 2013. Adults in the poll were more likely to be current marijuana smokers if they were male, under age 29 and had an annual income of less than $30,000 a year, Gallup said.