| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 2017 |
88.8%
|
| 2 | SOME DIFFICULTY | 210 |
9.2%
|
| 3 | A LOT OF DIFFICULTY | 18 |
0.8%
|
| 4 | CANNOT CONCENTRATE AT ALL | 16 |
0.7%
|
| Sysmiss | 11 |
0.5%
|