| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 10 |
8.9%
|
|
| 1992 | 10 |
8.9%
|
|
| 1993 | 21 |
18.8%
|
|
| 1994 | 17 |
15.2%
|
|
| 1995 | 29 |
25.9%
|
|
| 1996 | 25 |
22.3%
|
|
| Sysmiss | 19 |