| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 0 |
0%
|
| 1 | Much less effective | 33 |
2.8%
|
| 2 | Somewhat less effective | 109 |
9.1%
|
| 3 | Made no difference | 291 |
24.3%
|
| 4 | Somewhat more effective | 357 |
29.8%
|
| 5 | Much more effective | 347 |
28.9%
|
| 8 | Refused | 2 |
0.2%
|
| 9 | Don’t know | 61 |
5.1%
|