| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 287 |
21%
|
| 0 | 1074 |
78.5%
|
|
| 5 | 3 |
0.2%
|
|
| 10 | 4 |
0.3%
|
|
| 20 | 1 |
0.1%
|