Total US
According to the National Survey on Drug Use and Health (NSDUH), in 2008-2009, an estimated 13.37% of young people in the US aged 12 through 17 had used marijuana in the past year, falling to 12.29% in 2015-2016. The NSDUH also estimates that, in 2008-2009, an estimated 7.03% of young people in the US aged 12 through 17 had used marijuana in the past month, dropping to 6.75% in 2015-2016.
Colorado State
According to the NSDUH, in 2008-2009, an estimated 18.55% of young people in Colorado aged 12 through 17 had used marijuana in the past year, falling to 16.21% in 2015-2016. The NSDUH also estimates that, in 2008-2009, an estimated 10.17% of young people in Colorado aged 12 through 17 had used marijuana in the past month, dropping to 9.08% in 2015-2016.
Table: Prevalence of marijuana use in Colorado before and after passage and implementation of Amendment 64
Substance Abuse and Mental Health Services Administration. (2017). National Survey on Drug Use and Health: Comparison of 2008-2009 and 2015-2016 Population Percentages (50 States and the District of Columbia). Rockville, MD: Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration.
Substance Abuse and Mental Health Services Administration. (2017). National Survey on Drug Use and Health: Comparison of 2014-2015 and 2015-2016 Population Percentages (50 States and the District of Columbia). Rockville, MD: Center for Behavioral Health Statistics and Quality, Substance Abuse and Mental Health Services Administration.
