| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 35 |
5.9%
|
| -8 | Refusal (spontaneous) | 33 |
5.5%
|
| 0 | 1 |
0.2%
|
|
| 3 | 1 |
0.2%
|
|
| 15 | 515 |
86.1%
|
|
| 16 | 12 |
2%
|
|
| 17 | 1 |
0.2%
|