| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 22 |
15.8%
|
|
| 2008 | 27 |
19.4%
|
|
| 2009 | 29 |
20.9%
|
|
| 2010 | 30 |
21.6%
|
|
| 2011 | 30 |
21.6%
|
|
| 2012 | 1 |
0.7%
|
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 621 |