| Value | Category | Cases | |
|---|---|---|---|
| 2002 | 2 |
2.1%
|
|
| 2003 | 2 |
2.1%
|
|
| 2004 | 16 |
16.5%
|
|
| 2005 | 37 |
38.1%
|
|
| 2006 | 39 |
40.2%
|
|
| 9999 | 9999. Don't know | 1 |
1%
|
| Sysmiss | 902 |