| Value | Category | Cases | |
|---|---|---|---|
| -2 | No answer | 4 |
0.2%
|
| -1 | Don't know | 4 |
0.2%
|
| 1 | Lower | 552 |
31.7%
|
| 2 | Middle | 917 |
52.7%
|
| 3 | Higher | 264 |
15.2%
|