| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 53 |
3.1%
|
| -8 | REF (spontaneous) | 33 |
1.9%
|
| 1 | Yes | 147 |
8.5%
|
| 2 | No | 1493 |
86.5%
|
| Sysmiss | 1 |