| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 213 |
10.8%
|
|
| 1997 | 298 |
15.1%
|
|
| 1998 | 380 |
19.3%
|
|
| 1999 | 534 |
27.1%
|
|
| 2000 | 542 |
27.5%
|
|
| 9997 | inconsistent | 2 |
0.1%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 2020 |