| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 5 |
19.2%
|
|
| 1997 | 4 |
15.4%
|
|
| 1998 | 3 |
11.5%
|
|
| 1999 | 5 |
19.2%
|
|
| 2000 | 9 |
34.6%
|
|
| 9997 | Missing | 0 |
0%
|
| Sysmiss | 1864 |