| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 3 | 
                                    
                                    2.2%
                                 | 
| 2 | 2 | 
                                    
                                    1.5%
                                 | |
| 3 | 6 | 
                                    
                                    4.5%
                                 | |
| 4 | 7 | 
                                    
                                    5.2%
                                 | |
| 5 | 22 | 
                                    
                                    16.4%
                                 | |
| 6 | 17 | 
                                    
                                    12.7%
                                 | |
| 7 | 23 | 
                                    
                                    17.2%
                                 | |
| 8 | 9 | 
                                    
                                    6.7%
                                 | |
| 9 | 3 | 
                                    
                                    2.2%
                                 | |
| 10 | Very effective | 10 | 
                                    
                                    7.5%
                                 | 
| 11 | Don't know | 32 | 
                                    
                                    23.9%
                                 |