| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
0.1%
|
|
| 2007 | 152 |
12.6%
|
|
| 2008 | 245 |
20.3%
|
|
| 2009 | 308 |
25.5%
|
|
| 2010 | 350 |
28.9%
|
|
| 2011 | 153 |
12.7%
|
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 713 |