| Value | Category | Cases | |
|---|---|---|---|
| 2003 | 1 |
0%
|
|
| 2004 | 56 |
2.2%
|
|
| 2005 | 182 |
7.1%
|
|
| 2006 | 338 |
13.2%
|
|
| 2007 | 425 |
16.6%
|
|
| 2008 | 447 |
17.5%
|
|
| 9999 | Missing | 1105 |
43.3%
|
| Sysmiss | 11690 |