| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 15 |
2.2%
|
|
| 2008 | 100 |
14.9%
|
|
| 2009 | 135 |
20.1%
|
|
| 2010 | 148 |
22%
|
|
| 2011 | 175 |
26%
|
|
| 2012 | 98 |
14.6%
|
|
| 9999 | Missing | 2 |
0.3%
|
| Sysmiss | 2457 |