| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 1 |
16.7%
|
|
| 2002 | 1 |
16.7%
|
|
| 2005 | 2 |
33.3%
|
|
| 2007 | 1 |
16.7%
|
|
| 2009 | 1 |
16.7%
|
|
| Sysmiss | 1533 |