According to the National Survey on Drug Use and Health, in the United States in 2015 among people aged 12 and older there were an estimated 18,328,000 lifetime users of MDMA, 2,560,000 past-year users, and 557,000 past-month users.

Source

Center for Behavioral Health Statistics and Quality. (2016). 2015 National Survey on Drug Use and Health: Detailed Tables. Substance Abuse and Mental Health Services Administration, Rockville, MD, p. 178, Table 1.1A.
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