| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 1 |
0.1%
|
| 0 | Never | 114 |
9.4%
|
| 1 | Once or twice | 188 |
15.6%
|
| 2 | Several times | 135 |
11.2%
|
| 3 | Many times | 96 |
7.9%
|
| 7 | Not applicable/Saw no problems | 673 |
55.7%
|
| 9 | Don't know | 1 |
0.1%
|
| 998 | Refused | 0 |
0%
|