| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 15 |
2.2%
|
|
| 2008 | 99 |
14.8%
|
|
| 2009 | 135 |
20.2%
|
|
| 2010 | 147 |
22%
|
|
| 2011 | 175 |
26.2%
|
|
| 2012 | 96 |
14.4%
|
|
| 9999 | Missing | 1 |
0.1%
|
| Sysmiss | 2462 |