| Value | Category | Cases | |
|---|---|---|---|
| -2 | don't know | 3 |
42.9%
|
| -1 | 1 |
14.3%
|
|
| 1989 | 1 |
14.3%
|
|
| 2004 | 1 |
14.3%
|
|
| 2009 | 1 |
14.3%
|
|
| Sysmiss | 1042 |