| Value | Category | Cases | |
|---|---|---|---|
| 2004 | 4 |
1.6%
|
|
| 2005 | 26 |
10.4%
|
|
| 2006 | 40 |
15.9%
|
|
| 2007 | 86 |
34.3%
|
|
| 2008 | 93 |
37.1%
|
|
| 2009 | 1 |
0.4%
|
|
| 9997 | Inconsistent | 1 |
0.4%
|
| 9998 | DK | 0 |
0%
|
| Sysmiss | 8193 |