| Value | Category | Cases | |
|---|---|---|---|
| 1990 | 720 |
85.4%
|
|
| 1991 | 26 |
3.1%
|
|
| 1992 | 28 |
3.3%
|
|
| 1993 | 18 |
2.1%
|
|
| 1994 | 22 |
2.6%
|
|
| 1995 | 15 |
1.8%
|
|
| 1996 | 8 |
0.9%
|
|
| 1997 | 6 |
0.7%
|
|
| Sysmiss | 78 |