| Value | Category | Cases | |
|---|---|---|---|
| 1997 | 2 |
1.9%
|
|
| 1998 | 35 |
33%
|
|
| 1999 | 34 |
32.1%
|
|
| 2000 | 35 |
33%
|
|
| Sysmiss | 11538 |