| Value | Category | Cases | |
|---|---|---|---|
| 1990 | 1 |
20%
|
|
| 1993 | 1 |
20%
|
|
| 1995 | 1 |
20%
|
|
| 1998 | 1 |
20%
|
|
| 2000 | 1 |
20%
|
|
| Sysmiss | 1777 |