| Value | Category | Cases | |
|---|---|---|---|
| 2007 | 3 |
1.4%
|
|
| 2008 | 12 |
5.4%
|
|
| 2009 | 14 |
6.3%
|
|
| 2010 | 84 |
38%
|
|
| 2011 | 92 |
41.6%
|
|
| 9997 | Inconsistent (Secondary Editing) | 0 |
0%
|
| 9999 | Missing | 16 |
7.2%
|
| Sysmiss | 4551 |