Source: https://store.samhsa.gov/sites/default/files/SAMHSA_Digital_Download/PEP21-03-11-002.pdf Time period covered by the 2020 RTC: The 2020 RTC primarily includes data from calendar year 2019. Epidemiological data in Chapters 1, 2, and 3 draw primarily from the 2018 National Survey on Drug Use...