| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 1 |
6.7%
|
|
| 1992 | 3 |
20%
|
|
| 1993 | 1 |
6.7%
|
|
| 1994 | 2 |
13.3%
|
|
| 1996 | 1 |
6.7%
|
|
| 1997 | 1 |
6.7%
|
|
| 1998 | 3 |
20%
|
|
| 2000 | 2 |
13.3%
|
|
| 2001 | 1 |
6.7%
|
|
| Sysmiss | 1767 |