| Value | Category | Cases | |
|---|---|---|---|
| 1990 | 370 |
71.3%
|
|
| 1991 | 18 |
3.5%
|
|
| 1992 | 17 |
3.3%
|
|
| 1993 | 20 |
3.9%
|
|
| 1994 | 20 |
3.9%
|
|
| 1995 | 25 |
4.8%
|
|
| 1996 | 33 |
6.4%
|
|
| 1997 | 16 |
3.1%
|
|
| Sysmiss | 402 |