| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 3 | 
                                    
                                    1.3%
                                 | 
| 2 | 2 | 
                                    
                                    0.9%
                                 | |
| 3 | 11 | 
                                    
                                    4.9%
                                 | |
| 4 | 18 | 
                                    
                                    8%
                                 | |
| 5 | 14 | 
                                    
                                    6.2%
                                 | |
| 6 | 21 | 
                                    
                                    9.3%
                                 | |
| 7 | 25 | 
                                    
                                    11.1%
                                 | |
| 8 | 34 | 
                                    
                                    15.1%
                                 | |
| 9 | 29 | 
                                    
                                    12.9%
                                 | |
| 10 | Very effective | 68 | 
                                    
                                    30.2%
                                 | 
| 11 | Don't know | 44 | |
| Sysmiss | 50 |