| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 3717 |
93.7%
|
| 2 | Some difficulty | 217 |
5.5%
|
| 3 | A lot of difficulty | 26 |
0.7%
|
| 4 | Cannot concentrate at all | 3 |
0.1%
|
| 9 | No response | 4 |
0.1%
|
| Sysmiss | 362 |