| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 |
0%
|
| -9 | Don't know (spontaneous) | 28 |
3.5%
|
| 1 | Yes | 104 |
12.9%
|
| 2 | No | 674 |
83.6%
|
| Sysmiss | 640 |