| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 11 |
4.7%
|
| 0 | 193 |
82.8%
|
|
| 10 | 5 |
2.1%
|
|
| 20 | 17 |
7.3%
|
|
| 25 | 5 |
2.1%
|
|
| 30 | 2 |
0.9%
|