| Value | Category | Cases | |
|---|---|---|---|
| -1 | Missing | 2 |
0.2%
|
| 0 | Not at all effective | 48 |
4%
|
| 1 | Not very effective | 134 |
11.2%
|
| 2 | Somewhat effective | 521 |
43.4%
|
| 3 | Very effective | 362 |
30.2%
|
| 9 | Don't know | 133 |
11.1%
|
| 998 | Refused | 0 |
0%
|