| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 49973 |
72.7%
|
| 2 | SOME DIFFICULTY | 6998 |
10.2%
|
| 3 | A LOT OF DIFFICULTY | 711 |
1%
|
| 4 | CANNOT SEE AT ALL | 16 |
0%
|
| 9 | NO RESPONSE | 1 |
0%
|
| Sysmiss | 11010 |
16%
|