| Value | Category | Cases | |
|---|---|---|---|
| 0 | no difficulty | 7713 |
94.2%
|
| 1 | Some difficulty | 311 |
3.8%
|
| 2 | Great difficulty | 146 |
1.8%
|
| 3 | Can not completely | 13 |
0.2%
|
| Sysmiss | 6 |