| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 5 |
20%
|
|
| 1997 | 4 |
16%
|
|
| 1998 | 4 |
16%
|
|
| 1999 | 4 |
16%
|
|
| 2000 | 8 |
32%
|
|
| 9997 | Missing | 0 |
0%
|
| Sysmiss | 1865 |