| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 3775 |
98.6%
|
| 2 | Some difficulty | 41 |
1.1%
|
| 3 | A lot of difficulty | 3 |
0.1%
|
| 4 | Cannot do at all | 2 |
0.1%
|
| 99 | Refused | 8 |
0.2%
|
| Sysmiss | 316 |