| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 10 |
0.8%
|
| 0 | Never | 295 |
24.6%
|
| 1 | Once or twice | 169 |
14.1%
|
| 2 | Several times | 210 |
17.5%
|
| 3 | Many times | 41 |
3.4%
|
| 7 | Not applicable/Saw no problems | 469 |
39.1%
|
| 9 | Don't know | 6 |
0.5%
|