| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 4825 |
58.5%
|
| 2 | Minor difficult | 723 |
8.8%
|
| 3 | Big difficulty | 1655 |
20.1%
|
| 8 | NA | 1013 | |
| 9 | I don’t know | 11 | |
| Sysmiss | 17 |