| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 5 |
1.4%
|
| 0 | 352 |
97.8%
|
|
| 10 | 1 |
0.3%
|
|
| 20 | 1 |
0.3%
|
|
| 30 | 1 |
0.3%
|