The number of adults who said they use marijuana almost doubled over a three-year time period, according to a Gallup poll released 8 August 2016. The 13 percent of people who now say they use the drug represents a dramatic increase from a 2013 survey, and CNN reports that 43 percent said they have used it in the past: 

Among those who participated in the survey, one in eight — 13% — reported current marijuana use, and 43% said they have tried the drug, an increase from 38% in 2013. The percentage of pot smokers was 7% in the 2013 Gallup survey.

The results were based on phone interviews with 1,000 randomly-chosen adults. A 2014 study by the National Survey on Drug Use and Health found marijuana to be the most commonly-used drug among people aged 12 and older:

As noted in the illicit drug use section, an estimated 22.2 million Americans aged 12 or older in 2014 were current users of marijuana. This number of past month marijuana users corresponds to 8.4 percent of the population aged 12 or older. The percentage of people aged 12 or older who were current marijuana users in 2014 was higher than the percentages from 2002 to 2013.

The number of states that have legalized recreational marijuana use has doubled between 2013 and 2016. The four states that have legalized marijuana use are Colorado, Washington, Alaska and Oregon, and according to Gallup, half of U.S. states have some form of law permitting use of medicinal marijuana:

States’ willingness to legalize marijuana could be a reason for the uptick in the percentage of Americans who say they smoke marijuana, regardless of whether it is legal in their particular state. Gallup finds residents in the West — home of all four states that have legalized recreational marijuana use — are significantly more likely to say they smoke marijuana than those in other parts of the country.

Nine more states are set to vote on various levels of marijuana legalization in 2016.