| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 |
0.8%
|
| -7 | Does not apply (spontaneous) | 7 |
1.9%
|
| 1 | Very easy | 143 |
37.8%
|
| 2 | Easy | 155 |
41%
|
| 3 | Difficult | 60 |
15.9%
|
| 4 | Very Difficult | 10 |
2.6%
|
| Sysmiss | 641 |