| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 1602 |
96.2%
|
| 2 | SOME DIFFICULTY | 21 |
1.3%
|
| 3 | A LOT OF DIFFICULTY | 4 |
0.2%
|
| 4 | CANNOT SEE AT ALL | 1 |
0.1%
|
| Sysmiss | 38 |
2.3%
|