| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 2 |
2.9%
|
| 0 | None | 56 |
80%
|
| 1 | 11 |
15.7%
|
|
| 2 | 1 |
1.4%
|
|
| Sysmiss | 332 |