| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 2644666 |
98%
|
| 2 | Yes, some difficulty | 43648 |
1.6%
|
| 3 | Yes, a lot of difficulty | 8871 |
0.3%
|
| 4 | Cannot remember or concentrate at all | 1613 |
0.1%
|
| Sysmiss | 384774 |