| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 3 |
14.3%
|
|
| 1997 | 2 |
9.5%
|
|
| 1998 | 5 |
23.8%
|
|
| 1999 | 9 |
42.9%
|
|
| 2000 | 2 |
9.5%
|
|
| 9997 | Missing | 0 |
0%
|
| Sysmiss | 1869 |