| Value | Category | Cases | |
|---|---|---|---|
| 1 | Very easy | 344 |
1.8%
|
| 2 | Easy | 1474 |
7.7%
|
| 3 | Difficult | 5762 |
30.1%
|
| 4 | Very difficult | 6767 |
35.3%
|
| 5 | Don't know | 4803 |
25.1%
|