| Value | Category | Cases | |
|---|---|---|---|
| 1 | Very easy | 1484 |
67.5%
|
| 2 | Easy | 597 |
27.2%
|
| 3 | Difficult | 42 |
1.9%
|
| 4 | Very difficult | 51 |
2.3%
|
| 9 | Don't know | 24 |
1.1%
|