| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 3 |
0.3%
|
|
| 2007 | 68 |
6.5%
|
|
| 2008 | 217 |
20.7%
|
|
| 2009 | 280 |
26.7%
|
|
| 2010 | 327 |
31.1%
|
|
| 2011 | 155 |
14.8%
|
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 872 |