| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
0.6%
|
|
| 2007 | 6 |
3.7%
|
|
| 2008 | 2 |
1.2%
|
|
| 2009 | 10 |
6.1%
|
|
| 2010 | 61 |
37.2%
|
|
| 2011 | 30 |
18.3%
|
|
| 9997 | Inconsistent (Secondary Editing) | 0 |
0%
|
| 9999 | Missing | 54 |
32.9%
|
| Sysmiss | 4663 |