| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 2 |
0.1%
|
|
| 1996 | 348 |
19.5%
|
|
| 1997 | 440 |
24.7%
|
|
| 1998 | 391 |
21.9%
|
|
| 1999 | 396 |
22.2%
|
|
| 2000 | 205 |
11.5%
|
|
| 9997 | Missing | 0 |
0%
|
| Sysmiss | 839 |