| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 7 |
14.6%
|
|
| 2007 | 6 |
12.5%
|
|
| 2008 | 13 |
27.1%
|
|
| 2009 | 12 |
25%
|
|
| 2010 | 10 |
20.8%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 356 |