| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 20 |
15.4%
|
|
| 2008 | 22 |
16.9%
|
|
| 2009 | 25 |
19.2%
|
|
| 2010 | 29 |
22.3%
|
|
| 2011 | 33 |
25.4%
|
|
| 2012 | 1 |
0.8%
|
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 630 |