| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 |
0%
|
| -9 | Don't know (spontaneous) | 18 |
3%
|
| 1 | Yes | 87 |
14.6%
|
| 2 | No | 492 |
82.4%
|
| Sysmiss | 104 |