The estimated substance use rates were then applied to school enrollment data of 1994-95 to estimate the number of students in grades 5 to 12 who used substances in the 30 days prior to the survey dates. Figure 1 presents the percent of students who recently used substances by grades and type of substance used.
Solid lines indicate reported survey measures and dotted lines indicate estimated ones.
We assumed that there is no substance use before grade 5. The slopes of the lines show that substance use increases by grade, levels off between grades 10 and 11 and increases for 12th graders to a level higher than that found in the adult household survey. Dropouts may explain part of the leveling off of the slopes of the curves between the 10th and 11th grades, especially if dropouts concentrate in these grades and have higher prevalence than those who did not dropout. Table 1 shows the number of recent substance users by grade and substance. This means that two out of every five students in grades 5 to 12 in New Jersey have used some substance in the last 30 days prior to the survey date.