| Value | Category | Cases | |
|---|---|---|---|
| 1 | No difficulty | 1721 |
78.1%
|
| 2 | Minor difficult | 203 |
9.2%
|
| 3 | Big difficulty | 150 |
6.8%
|
| 8 | NA | 124 |
5.6%
|
| 9 | I don’t know | 4 |
0.2%
|
| Sysmiss | 2 |