| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 11 |
0.9%
|
| 0 | Never | 387 |
32.3%
|
| 1 | Once or twice | 159 |
13.3%
|
| 2 | Several times | 149 |
12.4%
|
| 3 | Many times | 21 |
1.8%
|
| 7 | Not applicable/Saw no problems | 469 |
39.1%
|
| 9 | Don't know | 4 |
0.3%
|