| Value | Category | Cases | |
|---|---|---|---|
| 2008 | 23 |
0.2%
|
|
| 2009 | 745 |
5.5%
|
|
| 2010 | 78 |
0.6%
|
|
| 9999 | Missing | 126 |
0.9%
|
| Sysmiss | 12615 |
92.8%
|