| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 24 |
3.3%
|
|
| 1996 | 70 |
9.6%
|
|
| 1997 | 89 |
12.2%
|
|
| 1998 | 140 |
19.2%
|
|
| 1999 | 235 |
32.2%
|
|
| 2000 | 76 |
10.4%
|
|
| 9997 | Missing | 96 |
13.2%
|
| Sysmiss | 1974 |