| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 16 |
1.6%
|
| -7 | Does not apply (spontaneous) | 51 |
5%
|
| 1 | Very easy | 70 |
6.9%
|
| 2 | Easy | 481 |
47.2%
|
| 3 | Difficult | 314 |
30.8%
|
| 4 | Very Difficult | 87 |
8.5%
|