"• Among adults aged 50 to 64, the rate of current illicit drug use increased from 2.7 percent in 2002 to 6.0 percent in 2013. For adults aged 50 to 54, the rate increased from 3.4 percent in 2002 to 7.9 percent in 2013 (Figure 2.10). Among those aged 55 to 59, the rate of current illicit drug use increased from 1.9 percent in 2002 to 5.7 percent in 2013. Among those aged 60 to 64, the rate of current illicit drug use increased from 1.1 percent in 2003 and 2004 to 3.9 percent in 2013."

Source

Substance Abuse and Mental Health Services Administration, Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings, NSDUH Series H-48, HHS Publication No. (SMA) 14-4863. Rockville, MD: Substance Abuse and Mental Health Services Administration, 2014, p. 24.
http://www.samhsa.gov/data/NS…
http://www.samhsa.gov/data/NS…