| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 82 |
5.6%
|
|
| 1997 | 158 |
10.8%
|
|
| 1998 | 250 |
17.1%
|
|
| 1999 | 439 |
30.1%
|
|
| 2000 | 531 |
36.4%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 5295 |