| Value | Category | Cases | |
|---|---|---|---|
| 1 | NO DIFFICULTY | 5007 |
91.4%
|
| 2 | SOME DIFFICULTY | 312 |
5.7%
|
| 3 | A LOT OF DIFFICULTY | 31 |
0.6%
|
| 4 | CANNOT SEE AT ALL | 9 |
0.2%
|
| Sysmiss | 120 |
2.2%
|