| Value | Category | Cases | |
|---|---|---|---|
| 1 | no difficulty seeing | 41621 |
87%
|
| 2 | some difficulty | 4779 |
10%
|
| 3 | a lot of difficulty | 1425 |
3%
|
| 4 | cannot see at all | 24 |
0.1%
|
| 8 | don't know | 2 |
0%
|
| Sysmiss | 8069 |