| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 2523 |
97.5%
|
| 2 | SOME DIFFICULTY | 58 |
2.2%
|
| 3 | A LOT OF DIFFICULTY | 5 |
0.2%
|
| 4 | CANNOT SEE AT ALL | 1 |
0%
|
| 9 | NO RESPONSE | 0 |
0%
|
| Sysmiss | 6830 |