| Value | Category | Cases | |
|---|---|---|---|
| 2003 | 6 |
24%
|
|
| 2004 | 7 |
28%
|
|
| 2005 | 8 |
32%
|
|
| 2006 | 4 |
16%
|
|
| 9998 | Dk | 0 |
0%
|
| 9999 | Missing | 0 |
0%
|
| Sysmiss | 167 |