| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 46 |
4.2%
|
| 0 | 4 |
0.4%
|
|
| 1 | 96 |
8.8%
|
|
| 2 | 405 |
37%
|
|
| 3 | 275 |
25.1%
|
|
| 4 | 270 |
24.6%
|