| Value | Category | Cases | |
|---|---|---|---|
| 2006 | 1 |
0.5%
|
|
| 2007 | 2 |
0.9%
|
|
| 2008 | 13 |
5.9%
|
|
| 2009 | 19 |
8.6%
|
|
| 2010 | 74 |
33.6%
|
|
| 2011 | 94 |
42.7%
|
|
| 9997 | Inconsistent (Secondary Editing) | 5 |
2.3%
|
| 9999 | Missing | 12 |
5.5%
|
| Sysmiss | 4552 |