| Value | Category | Cases | |
|---|---|---|---|
| 1996 | 171 |
9.5%
|
|
| 1997 | 287 |
15.9%
|
|
| 1998 | 331 |
18.4%
|
|
| 1999 | 472 |
26.2%
|
|
| 2000 | 542 |
30.1%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 2186 |