Table 1.
Patterns of NMPO use from adolescence into emerging adulthood.
| Females % |
Males % |
Total % |
|
|---|---|---|---|
| Used Grade 10 (n = 846)a | 13.1 | 11.6 | 12.3 |
| Used Grade 11 (n = 839) | 17.9 | 16.3 | 17.0 |
| Used Grade 12 (n = 838) | 20.3 | 18.2 | 19.2 |
| Used age 19 (n = 859) | 15.7 | 15.5 | 15.6 |
| Used age 20 (n = 870) | 13.6 | 11.8 | 12.6 |
| Used in high school (n = 754) | 28.8 | 27.8 | 28.2 |
| Used at age 19 and/or 20 (n = 754) | 20.8 | 19.4 | 20.0 |
| Ever used (n = 754) | 33.6 | 35.0 | 34.4 |
| Maximum frequencyb of use | 11.25 (11.98) | 11.49 (11.98) | 11.38 (11.98) |
| Mean frequency Grade 10 | 9.46 (11.73) | 8.10 (10.03) | 8.78 (10.88) |
| Mean frequency Grade 11 | 7.39 (9.05) | 11.08 (12.27)* | 9.27 (10.94) |
| Mean frequency Grade 12 | 8.21 (9.00) | 8.90 (8.98) | 8.55 (8.97) |
| Mean frequency age 19 | 7.06 (7.56) | 10.07 (11.41) | 8.66 (9.87) |
| Mean frequency age 20 | 10.21 (11.62) | 13.23 (12.98) | 11.69 (12.34) |
| Average age of first use between Grade 10 and age 20 among those who ever used |
17.11 (1.13) | 17.33 (1.21) | 17.23 (1.18) |
| Number of years used among those who ever used |
2.31 (1.23) | 2.04 (1.22) | 2.17 (1.22) |
a
Percentages for yearly data are based on cases with nonmissing data.
b
Frequency was recoded as: '1 – 2 times' = 1.5, '3 – 5 times' = 4, '6 – 9 times' = 7.5, '10 – 19 times' = 14.5, '20 – 39 times' = 29.5, '40+ times' = 40.
*
Significantly different at the .05-level in a two-tailed test.