| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 2 |
0.2%
|
| 0 | Not at all effective | 55 |
4.6%
|
| 1 | Not very effective | 71 |
5.9%
|
| 2 | Somewhat effective | 200 |
16.7%
|
| 3 | Very effective | 860 |
71.7%
|
| 9 | Don't know | 11 |
0.9%
|
| 98 | Refused | 0 |
0%
|