| Value | Category | Cases | |
|---|---|---|---|
| 1997 | 4 |
3.1%
|
|
| 1998 | 2 |
1.5%
|
|
| 1999 | 4 |
3.1%
|
|
| 2000 | 4 |
3.1%
|
|
| 2001 | 11 |
8.5%
|
|
| 2002 | 19 |
14.6%
|
|
| 2003 | 42 |
32.3%
|
|
| 2004 | 44 |
33.8%
|
|
| Sysmiss | 203 |