| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 2 |
9.1%
|
|
| 1997 | 3 |
13.6%
|
|
| 1998 | 4 |
18.2%
|
|
| 1999 | 11 |
50%
|
|
| 2000 | 2 |
9.1%
|
|
| 9997 | Missing | 0 |
0%
|
| Sysmiss | 1868 |