| Value | Category | Cases | |
|---|---|---|---|
| 2004 | 168 |
21.1%
|
|
| 2005 | 272 |
34.2%
|
|
| 2006 | 232 |
29.1%
|
|
| 2007 | 92 |
11.6%
|
|
| 2008 | 17 |
2.1%
|
|
| 2009 | 1 |
0.1%
|
|
| 9997 | Inconsistent | 14 |
1.8%
|
| 9998 | DK | 0 |
0%
|
| Sysmiss | 7648 |