"In 2018, nearly 1 in 5 people aged 12 or older (19.4 percent) used an illicit drug in the past year, which is a higher percentage than in 2015 and 2016. The estimate of past year illicit drug use for 2018 was driven primarily by marijuana use, with 43.5 million past year marijuana users. The percentage of people aged 12 or older in 2018 who used marijuana in the past year (15.9 percent) was higher than the percentages in 2002 to 2017.