| Value | Category | Cases | |
|---|---|---|---|
| 1995 | 3 |
6.8%
|
|
| 1996 | 20 |
45.5%
|
|
| 1997 | 11 |
25%
|
|
| 1998 | 10 |
22.7%
|
|
| Sysmiss | 8464 |