| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
3.7%
|
|
| 2007 | 2 |
7.4%
|
|
| 2008 | 2 |
7.4%
|
|
| 2009 | 8 |
29.6%
|
|
| 2010 | 14 |
51.9%
|
|
| 9997 | inconsistent | 0 |
0%
|
| 9998 | dk | 0 |
0%
|
| Sysmiss | 377 |