| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 22 |
3%
|
|
| 2008 | 113 |
15.4%
|
|
| 2009 | 133 |
18.2%
|
|
| 2010 | 169 |
23.1%
|
|
| 2011 | 181 |
24.7%
|
|
| 2012 | 113 |
15.4%
|
|
| 9999 | Missing | 1 |
0.1%
|
| Sysmiss | 2398 |