| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 |
0%
|
| 1 | Higher than usual | 2 |
10%
|
| 2 | Lower than usual | 8 |
40%
|
| 3 | The usual | 10 |
50%
|
| Sysmiss | 91 |