| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 27 |
4.4%
|
| 0 | 575 |
94%
|
|
| 10 | 4 |
0.7%
|
|
| 20 | 3 |
0.5%
|
|
| 30 | 1 |
0.2%
|
|
| 44 | 1 |
0.2%
|
|
| 50 | 1 |
0.2%
|