| Value | Category | Cases | |
|---|---|---|---|
| 0 | no difficulty | 7858 |
96%
|
| 1 | Some difficulty | 212 |
2.6%
|
| 2 | Great difficulty | 99 |
1.2%
|
| 3 | Can not completely | 14 |
0.2%
|
| Sysmiss | 6 |