| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 2 |
13.3%
|
|
| 2007 | 3 |
20%
|
|
| 2008 | 4 |
26.7%
|
|
| 2009 | 6 |
40%
|
|
| Sysmiss | 126 |