| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 5 | 
                                    
                                    2.5%
                                 | 
| 2 | 5 | 
                                    
                                    2.5%
                                 | |
| 3 | 13 | 
                                    
                                    6.5%
                                 | |
| 4 | 13 | 
                                    
                                    6.5%
                                 | |
| 5 | 29 | 
                                    
                                    14.5%
                                 | |
| 6 | 34 | 
                                    
                                    17%
                                 | |
| 7 | 19 | 
                                    
                                    9.5%
                                 | |
| 8 | 26 | 
                                    
                                    13%
                                 | |
| 9 | 21 | 
                                    
                                    10.5%
                                 | |
| 10 | Very effective | 35 | 
                                    
                                    17.5%
                                 | 
| 11 | Don't know | 66 | |
| Sysmiss | 53 |