"As noted in the illicit drug use section, an estimated 26.0 million Americans aged 12 or older in 2017 were current users of marijuana (Figure 11). This number of past month marijuana users corresponds to 9.6 percent of the population aged 12 or older (Figure 13). The percentage of people aged 12 or older who were current marijuana users in 2017 was higher than the percentages from 2002 to 2016. This increase in marijuana use among people aged 12 or older reflects increases in marijuana use among both young adults aged 18 to 25 and adults aged 26 or older."

Source

Substance Abuse and Mental Health Services Administration. (2018). Key substance use and mental health indicators in the United States: Results from the 2017 National Survey on Drug Use and Health (HHS Publication No. SMA 18-5068, NSDUH Series H-53). Rockville, MD: Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration.