| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 76 |
28%
|
| 0 | 191 |
70.5%
|
|
| 10 | 1 |
0.4%
|
|
| 20 | 1 |
0.4%
|
|
| 40 | 1 |
0.4%
|
|
| 50 | 1 |
0.4%
|