| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 |
0%
|
| -9 | Don't know (spontaneous) | 11 |
1.4%
|
| 1 | Yes | 159 |
19.7%
|
| 2 | No | 636 |
78.9%
|
| Sysmiss | 640 |