| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
0.7%
|
|
| 2007 | 6 |
4.3%
|
|
| 2008 | 1 |
0.7%
|
|
| 2009 | 13 |
9.3%
|
|
| 2010 | 43 |
30.7%
|
|
| 2011 | 23 |
16.4%
|
|
| 9997 | Inconsistent (Secondary Editing) | 0 |
0%
|
| 9999 | Missing | 53 |
37.9%
|
| Sysmiss | 4687 |