| Value | Category | Cases | |
|---|---|---|---|
| 2005 | 4 |
16%
|
|
| 2008 | 3 |
12%
|
|
| 2011 | 4 |
16%
|
|
| 2012 | 5 |
20%
|
|
| 2013 | 2 |
8%
|
|
| 9998 | dont know | 7 |
28%
|
| Sysmiss | 16405 |