| Value | Category | Cases | |
|---|---|---|---|
| 1991 | 3 |
13.6%
|
|
| 1998 | 1 |
4.5%
|
|
| 2000 | 1 |
4.5%
|
|
| 2006 | 1 |
4.5%
|
|
| 2007 | 3 |
13.6%
|
|
| 2009 | 1 |
4.5%
|
|
| 2010 | 1 |
4.5%
|
|
| 2011 | 5 |
22.7%
|
|
| 2012 | 6 |
27.3%
|
|
| Sysmiss | 441 |