| Value | Category | Cases | |
|---|---|---|---|
| -99 | NA | 6987 |
93.1%
|
| -97 | Refused | 40 |
0.5%
|
| 1 | More comfortable | 135 |
1.8%
|
| 2 | Less comfortable | 147 |
2%
|
| 3 | No difference whether smoking or not | 193 |
2.6%
|