| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 1 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    
| 2 | 3 | 
                                                                 
                                    
                                    1.3%
                                 
                                                             | 
                                                        
                    |
| 3 | 2 | 
                                                                 
                                    
                                    0.9%
                                 
                                                             | 
                                                        
                    |
| 4 | 8 | 
                                                                 
                                    
                                    3.4%
                                 
                                                             | 
                                                        
                    |
| 5 | 15 | 
                                                                 
                                    
                                    6.4%
                                 
                                                             | 
                                                        
                    |
| 6 | 23 | 
                                                                 
                                    
                                    9.9%
                                 
                                                             | 
                                                        
                    |
| 7 | 36 | 
                                                                 
                                    
                                    15.5%
                                 
                                                             | 
                                                        
                    |
| 8 | 40 | 
                                                                 
                                    
                                    17.2%
                                 
                                                             | 
                                                        
                    |
| 9 | 31 | 
                                                                 
                                    
                                    13.3%
                                 
                                                             | 
                                                        
                    |
| 10 | Very effective | 33 | 
                                                                 
                                    
                                    14.2%
                                 
                                                             | 
                                                        
                    
| 11 | Don't know | 41 | 
                                                                 
                                    
                                    17.6%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 4 |