| Value | Category | Cases | |
|---|---|---|---|
| 0 | no difficulty | 8092 |
98.8%
|
| 1 | Some difficulty | 55 |
0.7%
|
| 2 | Great difficulty | 28 |
0.3%
|
| 3 | Can not completely | 8 |
0.1%
|
| Sysmiss | 6 |