According to UNODC, cannabis abuse in the United States is on the increase, including among high school students, for which annual prevalence rates rose from 24.7 per cent in 2012 to 25.8 per cent in 2013. The number of overdose deaths related to cocaine in 2013 saw a 12 per cent increase over 2012. The biggest increase in the number of overdose deaths identified was related to heroin.