| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 0 |
0%
|
| 1 | Very easy | 84 |
3.5%
|
| 2 | Easy | 149 |
6.2%
|
| 3 | Difficult | 777 |
32.4%
|
| 4 | Very difficult | 1231 |
51.3%
|
| 9 | Don't know | 159 |
6.6%
|