| Value | Category | Cases | |
|---|---|---|---|
| -99 | NA | 3526 |
75.4%
|
| -97 | Refused | 84 |
1.8%
|
| 1 | Very difficult | 249 |
5.3%
|
| 2 | Fairly difficult | 188 |
4%
|
| 3 | Fairly easy | 228 |
4.9%
|
| 4 | Very easy | 400 |
8.6%
|