| Value | Category | Cases | |
|---|---|---|---|
| 1 | Very easy | 72 |
3.3%
|
| 2 | Easy | 165 |
7.5%
|
| 3 | Difficult | 642 |
29.2%
|
| 4 | Very difficult | 1084 |
49.3%
|
| 9 | Don't know | 235 |
10.7%
|