| Value | Category | Cases | |
|---|---|---|---|
| 1 | a.No difficulty | 8111 |
35.1%
|
| 2 | b.Some difficulty | 214 |
0.9%
|
| 3 | c.A lot of difficulty | 67 |
0.3%
|
| 4 | d.Cannot do at all | 15 |
0.1%
|
| Missing value | 14731 |
63.7%
|