| Value | Category | Cases | |
|---|---|---|---|
| 1998 | 7 |
10.9%
|
|
| 1999 | 17 |
26.6%
|
|
| 2000 | 23 |
35.9%
|
|
| 2001 | 14 |
21.9%
|
|
| 2002 | 3 |
4.7%
|
|
| Sysmiss | 7985 |