| Value | Category | Cases | |
|---|---|---|---|
| 1 | No - no difficulty | 11929 |
94.3%
|
| 2 | Yes - some difficulty | 611 |
4.8%
|
| 3 | Yes – a lot of difficulty | 98 |
0.8%
|
| 4 | Cannot see at all | 7 |
0.1%
|
| Sysmiss | 48 |