| Value | Category | Cases | |
|---|---|---|---|
| 2002 | 1 |
10%
|
|
| 2003 | 1 |
10%
|
|
| 2005 | 4 |
40%
|
|
| 2006 | 4 |
40%
|
|
| 9999 | 9999. Don't know | 0 |
0%
|
| Sysmiss | 989 |