| Value | Category | Cases | |
|---|---|---|---|
| 1 | a.No difficulty | 13221 |
82.6%
|
| 2 | b.Some difficulty | 469 |
2.9%
|
| 3 | c.A lot of difficulty | 110 |
0.7%
|
| 4 | d.Cannot do at all | 22 |
0.1%
|
| Missing value | 2184 |
13.6%
|