| Value | Category | Cases | |
|---|---|---|---|
| 2002 | 7 |
4.8%
|
|
| 2003 | 19 |
13%
|
|
| 2004 | 47 |
32.2%
|
|
| 2005 | 64 |
43.8%
|
|
| 9999 | 9999. Don't know | 9 |
6.2%
|
| Sysmiss | 853 |