| Year | All Drugs | Cannabis | Percentage Cannabis |
|---|---|---|---|
| 1984 | 25240 | 20746 | 82.19 |
| 1985 | 26958 | 21337 | 79.14 |
| 1986 | 23905 | 19286 | 80.67 |
| 1987 | 26278 | 21733 | 82.70 |
| 1988 | 30515 | 26111 | 85.56 |
| 1989 | 38415 | 33669 | 87.64 |
| 1990 | 44922 | 40194 | 89.47 |
| 1991 | 47616 | 42209 | 88.64 |
| 1992 | 48927 | 41353 | 84.51 |
| 1993 | 68480 | 56390 | 82.34 |
| 1994 | 85693 | 72393 | 84.47 |
| 1995 | 93631 | 76694 | 81.91 |