| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
8%
|
| 0 | None | 20 |
80%
|
| 7 | 1 |
4%
|
|
| 10 | 1 |
4%
|
|
| 20 | 1 |
4%
|
|
| Sysmiss | 89 |