| Value | Category | Cases | |
|---|---|---|---|
| 1997 | 1 |
33.3%
|
|
| 1999 | 1 |
33.3%
|
|
| 2003 | 1 |
33.3%
|
|
| 9998 | Don't know | 0 |
0%
|
| Sysmiss | 42009 |