| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 |
0.2%
|
| 1 | Higher than usual | 0 |
0%
|
| 2 | Lower than usual | 16 |
3.1%
|
| 3 | The usual | 498 |
96.7%
|