| Value | Category | Cases | |
|---|---|---|---|
| 1997 | 1 |
5.9%
|
|
| 1998 | 2 |
11.8%
|
|
| 1999 | 4 |
23.5%
|
|
| 2000 | 5 |
29.4%
|
|
| 2001 | 1 |
5.9%
|
|
| 2002 | 4 |
23.5%
|
|
| Sysmiss | 8032 |