Illegal Drug Use and Marijuana Use in Lifetime, Past Year, and Past Month in the US

The National Survey on Drug Use and Health is conducted annually by the Substance Abuse and Mental Health Services Administration. According to NSDUH, in 2019:
138,027 people in the US aged 12 and older had used an illegal drug or marijuana in their lifetimes.
57,203 had used an illegal drug or marijuana in the previous year.
35,803 had used an illegal drug or marijuana in the previous month.

In 2018:
134,791 people in the US aged 12 and older had used an illegal drug or marijuana in their lifetimes.
53,182 had used an illegal drug in the previous year.
31,918 had used an illegal drug in the previous month.

NSDUH also reported that in 2019:
127,139 people in the US aged 12 or older had used marijuana in their lifetimes.
48,242 had used marijuana in the previous year.
31,606 had used marijuana in the previous month.

In 2018:
123,935 people in the US aged 12 or older had used marijuana in their lifetimes.
43,486 had used marijuana in the previous year.
27,667 had used marijuana in the previous month.

Source: 

Center for Behavioral Health Statistics and Quality. (2020). Results from the 2019 National Survey on Drug Use and Health: Detailed tables. Rockville, MD: Substance Abuse and Mental Health Services Administration.