| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 1 |
9.1%
|
|
| 1992 | 1 |
9.1%
|
|
| 1993 | 1 |
9.1%
|
|
| 1994 | 2 |
18.2%
|
|
| 1996 | 2 |
18.2%
|
|
| 1997 | 4 |
36.4%
|
|
| Sysmiss | 1642 |