| Value | Category | Cases | |
|---|---|---|---|
| 1997 | 1 |
3.2%
|
|
| 1998 | 1 |
3.2%
|
|
| 1999 | 5 |
16.1%
|
|
| 2000 | 9 |
29%
|
|
| 2001 | 13 |
41.9%
|
|
| 2002 | 2 |
6.5%
|
|
| Sysmiss | 11283 |