| Value | Category | Cases | |
|---|---|---|---|
| 2009 | 10 |
10.4%
|
|
| 2010 | 21 |
21.9%
|
|
| 2011 | 23 |
24%
|
|
| 2012 | 24 |
25%
|
|
| 2013 | 18 |
18.8%
|
|
| Sysmiss | 891 |