| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
0.3%
|
|
| 2007 | 3 |
0.8%
|
|
| 2008 | 19 |
5.2%
|
|
| 2009 | 34 |
9.3%
|
|
| 2010 | 138 |
37.9%
|
|
| 2011 | 160 |
44%
|
|
| 9997 | Inconsistent (Secondary Editing) | 3 |
0.8%
|
| 9999 | Missing | 6 |
1.6%
|
| Sysmiss | 4408 |