Figure 1 summarizes the percentages of participants showing risk behaviors from age 16 to age 29 (i.e., the prevalence of the risk behaviors). Alcohol was the most commonly used substance. Alcohol use increased rapidly from 66% at age 16 to 79% at age 19, then increased more slowly and finally remained stable around 88% at age 25 to 29. Drinking up to the point of drunkenness was reported by almost 25% of all participants at age 16. Drunkenness peaked from ages 22 to 24 with a 30-day prevalence of 35% and then decreased again to 27% at age 29, a similar level to that at age 16. Although the prevalence rate of smoking is higher, the trajectory is similar to that for drunkenness. At age 16, 37% of the participants smoked during the month prior to the interview. Smoking prevalence increased rapidly during late adolescence, remained relatively stable from age 21 to age 24 with a prevalence rate of almost 50% and then decreased again to 39% at age 29. Cannabis use was also common, with about 25% of the
