| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 44 |
7.9%
|
| 1 | Higher than usual | 40 |
7.2%
|
| 2 | Lower than usual | 98 |
17.7%
|
| 3 | The usual | 372 |
67.1%
|