| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
100%
|
| -7 | Does not apply (spontaneous) | 0 | |
| 1 | Very easy | 0 | |
| 2 | Easy | 0 | |
| 3 | Difficult | 0 | |
| 4 | Very Difficult | 0 |