| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 8 |
7.2%
|
|
| 2007 | 14 |
12.6%
|
|
| 2008 | 21 |
18.9%
|
|
| 2009 | 18 |
16.2%
|
|
| 2010 | 33 |
29.7%
|
|
| 2011 | 17 |
15.3%
|
|
| Sysmiss | 1915 |