| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 9 |
0.8%
|
| 0 | Not at all effective | 67 |
5.6%
|
| 1 | Not very effective | 283 |
23.6%
|
| 2 | Somewhat effective | 391 |
32.6%
|
| 3 | Very effective | 331 |
27.6%
|
| 9 | Don't know | 118 |
9.8%
|
| 998 | Refused | 0 |
0%
|