| Value | Category | Cases | |
|---|---|---|---|
| 2003 | 6 |
0.2%
|
|
| 2004 | 411 |
12.1%
|
|
| 2005 | 526 |
15.5%
|
|
| 2006 | 687 |
20.2%
|
|
| 2007 | 743 |
21.9%
|
|
| 2008 | 945 |
27.9%
|
|
| 2009 | 38 |
1.1%
|
|
| 9997 | Inconsistent | 37 |
1.1%
|
| 9998 | DK | 0 |
0%
|
| Sysmiss | 19141 |