| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 |
0%
|
| -9 | Don't know (spontaneous) | 6 |
9%
|
| 0 | 58 |
86.6%
|
|
| 9 | 1 |
1.5%
|
|
| 20 | 1 |
1.5%
|
|
| 70 | 1 |
1.5%
|
|
| Sysmiss | 84 |