Prevalence of cannabis use at each time point estimated using all available data
| 13 years | 14 years | 15 years | 16 years | 17 years | 18 years | |
|---|---|---|---|---|---|---|
| n=4664 | n=4571 | n=4427 | n=4196 | n=3550 | n=2939 | |
| Do not use | 4525 (97.0%) | 4470 (97.8%) | 4032 (91.1%) | 3782 (90.1%) | 2868 (80.8%) | 2457 (83.6%) |
| Occasional | 139 (3.0%) | 101 (2.2%) | 275 (6.2%) | 284 (6.8%) | 533 (15.0%) | 353 (12.0%) |
| Frequent | 0 (0.0%) | 0 (0.0%) | 120 (2.7%) | 130 (3.1%) | 149 (4.2%) | 129 (4.4%) |
Derivation of the three categories used here is provided in online supplementary table S1.