| Value | Category | Cases | |
|---|---|---|---|
| 1985 | 1 |
5%
|
|
| 1995 | 5 |
25%
|
|
| 1996 | 2 |
10%
|
|
| 1997 | 9 |
45%
|
|
| 1998 | 3 |
15%
|
|
| Sysmiss | 283 |