| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 1318 |
92.8%
|
| 2 | Some difficulty | 88 |
6.2%
|
| 3 | A lot of difficulty | 13 |
0.9%
|
| 4 | Cannot see at all | 2 |
0.1%
|
| Sysmiss | 1229 |