| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 1 |
6.3%
|
|
| 1997 | 3 |
18.8%
|
|
| 1998 | 3 |
18.8%
|
|
| 1999 | 4 |
25%
|
|
| 2000 | 5 |
31.3%
|
|
| 9997 | Missing | 0 |
0%
|
| Sysmiss | 1874 |