| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 8 |
1.4%
|
|
| 2008 | 82 |
14.6%
|
|
| 2009 | 117 |
20.9%
|
|
| 2010 | 123 |
21.9%
|
|
| 2011 | 153 |
27.3%
|
|
| 2012 | 77 |
13.7%
|
|
| 9999 | Missing | 1 |
0.2%
|
| Sysmiss | 2569 |