| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 13 |
3.6%
|
| 1 | Higher than usual | 38 |
10.5%
|
| 2 | Lower than usual | 50 |
13.9%
|
| 3 | The usual | 260 |
72%
|