| Value | Category | Cases | |
|---|---|---|---|
| 1988 | 2 |
28.6%
|
|
| 1994 | 1 |
14.3%
|
|
| 1996 | 2 |
28.6%
|
|
| 1998 | 2 |
28.6%
|
|
| Sysmiss | 14627 |