| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 1 |
5.6%
|
|
| 1997 | 1 |
5.6%
|
|
| 1999 | 10 |
55.6%
|
|
| 2000 | 6 |
33.3%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 12218 |