| Value | Category | Cases | |
|---|---|---|---|
| 2004 | 4 |
0.1%
|
|
| 2005 | 523 |
7%
|
|
| 2006 | 914 |
12.2%
|
|
| 2007 | 826 |
11%
|
|
| 2008 | 894 |
11.9%
|
|
| 2009 | 350 |
4.7%
|
|
| 9998 | dk | 10 |
0.1%
|
| 9999 | missing | 1234 |
16.5%
|
| Sysmiss | 2744 |
36.6%
|