| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 1349 |
94.9%
|
| 2 | Some difficulty | 60 |
4.2%
|
| 3 | A lot of difficulty | 10 |
0.7%
|
| 4 | Cannot concentrate at all | 2 |
0.1%
|
| Sysmiss | 1229 |