| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 25 |
29.1%
|
| 0 | None | 55 |
64%
|
| 1 | 5 |
5.8%
|
|
| 10 | 1 |
1.2%
|
|
| Sysmiss | 265 |