| Value | Category | Cases | |
|---|---|---|---|
| 2003 | 4 |
0.2%
|
|
| 2004 | 138 |
5.6%
|
|
| 2005 | 227 |
9.2%
|
|
| 2006 | 452 |
18.3%
|
|
| 2007 | 660 |
26.7%
|
|
| 2008 | 932 |
37.7%
|
|
| 2009 | 38 |
1.5%
|
|
| 9997 | Inconsistent | 20 |
0.8%
|
| 9998 | DK | 0 |
0%
|
| Sysmiss | 5973 |