| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 3 | 
                                    
                                    1.5%
                                 | 
| 2 | 1 | 
                                    
                                    0.5%
                                 | |
| 3 | 7 | 
                                    
                                    3.4%
                                 | |
| 4 | 11 | 
                                    
                                    5.3%
                                 | |
| 5 | 20 | 
                                    
                                    9.7%
                                 | |
| 6 | 24 | 
                                    
                                    11.7%
                                 | |
| 7 | 25 | 
                                    
                                    12.1%
                                 | |
| 8 | 36 | 
                                    
                                    17.5%
                                 | |
| 9 | 24 | 
                                    
                                    11.7%
                                 | |
| 10 | Very effective | 55 | 
                                    
                                    26.7%
                                 | 
| 11 | Don't know | 62 | |
| Sysmiss | 51 |