| Value | Category | Cases | |
|---|---|---|---|
| 2004 | 4 |
4.1%
|
|
| 2005 | 28 |
28.6%
|
|
| 2006 | 32 |
32.7%
|
|
| 2007 | 27 |
27.6%
|
|
| 2008 | 6 |
6.1%
|
|
| 9997 | Inconsistent | 1 |
1%
|
| 9998 | DK | 0 |
0%
|
| Sysmiss | 8346 |