| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 2 |
3.4%
|
|
| 1992 | 16 |
27.1%
|
|
| 1993 | 19 |
32.2%
|
|
| 1994 | 22 |
37.3%
|
|
| Sysmiss | 9642 |