| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 2522 |
90.3%
|
| 2 | SOME DIFFICULTY | 198 |
7.1%
|
| 3 | A LOT OF DIFFICULTY | 16 |
0.6%
|
| 4 | CANNOT SEE AT ALL | 3 |
0.1%
|
| Sysmiss | 55 |
2%
|