| Value | Category | Cases | |
|---|---|---|---|
| 2003 | 10 |
25.6%
|
|
| 2004 | 6 |
15.4%
|
|
| 2005 | 16 |
41%
|
|
| 2006 | 7 |
17.9%
|
|
| 9998 | DK | 0 |
0%
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 153 |