| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 1 |
3.2%
|
|
| 1999 | 6 |
19.4%
|
|
| 2000 | 15 |
48.4%
|
|
| 2001 | 9 |
29%
|
|
| Sysmiss | 11427 |