| Value | Category | Cases | |
|---|---|---|---|
| 1998 | 2 |
6.3%
|
|
| 1999 | 5 |
15.6%
|
|
| 2000 | 3 |
9.4%
|
|
| 2001 | 7 |
21.9%
|
|
| 2002 | 15 |
46.9%
|
|
| Sysmiss | 8017 |