| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 4 |
5.7%
|
|
| 2008 | 20 |
28.6%
|
|
| 2009 | 12 |
17.1%
|
|
| 2010 | 18 |
25.7%
|
|
| 2011 | 15 |
21.4%
|
|
| 2012 | 1 |
1.4%
|
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 690 |