"In line with a number of other studies, the 2013 survey shows that cannabis is by far the most common illegal drug in Norway. As shown in Figure 2, the LTP rate for cannabis use among all adults was 23.3 per cent, while the LYP rate was 5.1 per cent. By comparison, the LTP rate was estimated to be 4.2 per cent for cocaine, 3.7 per cent for amphetamines, 2.3 per cent for ecstasy, 1.5 per cent for LSD, 1.1 per cent for GHB/GBL and 0.7 per cent for heroin for all adults (Figure 3). The LYP rate was estimated to be less than one per cent for cocaine, amphetamines and ecstasy.

"Between 2007 and 2012 in the set of the Portuguese population there was a general decrease in lifetime prevalence6 (any illicit drug from 12% to 9.5%) and recent use (any illicit drug from 3.7% to 2.7%), with the exception of ecstasy and LSD, whose lifetime prevalence remained the same and LSD use in last 12 months increased slightly.

"In the study conducted in 2012 in the Portuguese General Population (15-64), cannabis, ecstasy and cocaine were the illicit substances preferably used by the Portuguese with lifetime prevalence (at least one use experience) respectively of 9.4%, 1.3% and 1.2%.

"The estimated 30.5 million people aged 12 or older who were current illicit drug users in 2017 represent 11.2 percent of the population aged 12 or older (Figures 11 and 12). Stated another way, 1 in 9 individuals aged 12 or older in the United States used illicit drugs in the past month. Approximately 2.0 million adolescents aged 12 to 17 in 2017 were current users of illicit drugs, which represents 7.9 percent of adolescents. Approximately 1 in 4 young adults aged 18 to 25 (24.2 percent) were current users of illicit drugs in 2017.

"In 2017, 30.5 million people aged 12 or older used an illicit drug in the past 30 days (i.e., current use), which corresponds to about 1 in 9 Americans (11.2 percent). About 1 in 4 young adults aged 18 to 25 were current illicit drug users. Regardless of age, the estimates of current illicit drug use for 2017 were driven primarily by marijuana use and the misuse of prescription pain relievers.

Data Table of Estimated 30-Day Prevalence of Use of Various Drugs for Young People in the US in Grades 8, 10, and 12 Combined, 1998 through 2016, According to the Monitoring The Future Survey