| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 11706 |
77.9%
|
| 2 | SOME DIFFICULTY | 1499 |
10%
|
| 3 | A LOT OF DIFFICULTY | 107 |
0.7%
|
| 4 | CAN NOT SEE AT ALL | 8 |
0.1%
|
| Sysmiss | 1699 |
11.3%
|