| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 |
0%
|
| -9 | Don't know (spontaneous) | 20 |
39.2%
|
| 0 | 19 |
37.3%
|
|
| 10 | 2 |
3.9%
|
|
| 12 | 1 |
2%
|
|
| 15 | 1 |
2%
|
|
| 20 | 2 |
3.9%
|
|
| 25 | 5 |
9.8%
|
|
| 30 | 1 |
2%
|
|
| Sysmiss | 99 |