| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 0 |
0%
|
| 1 | Very easy | 51 |
2.1%
|
| 2 | Easy | 200 |
8.3%
|
| 3 | Difficult | 732 |
30.5%
|
| 4 | Very difficult | 1149 |
47.9%
|
| 9 | Don't know | 265 |
11.1%
|