| Value | Category | Cases | |
|---|---|---|---|
| 2004 | 3 |
6.4%
|
|
| 2005 | 6 |
12.8%
|
|
| 2006 | 8 |
17%
|
|
| 2007 | 10 |
21.3%
|
|
| 2008 | 20 |
42.6%
|
|
| 9997 | Inconsistent | 0 |
0%
|
| 9998 | DK | 0 |
0%
|
| Sysmiss | 9010 |