| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 2 | 
                                                                 
                                    
                                    5%
                                 
                                                             | 
                                                        
                    
| 2 | 1 | 
                                                                 
                                    
                                    2.5%
                                 
                                                             | 
                                                        
                    |
| 3 | 2 | 
                                                                 
                                    
                                    5%
                                 
                                                             | 
                                                        
                    |
| 4 | 1 | 
                                                                 
                                    
                                    2.5%
                                 
                                                             | 
                                                        
                    |
| 5 | 5 | 
                                                                 
                                    
                                    12.5%
                                 
                                                             | 
                                                        
                    |
| 6 | 6 | 
                                                                 
                                    
                                    15%
                                 
                                                             | 
                                                        
                    |
| 7 | 6 | 
                                                                 
                                    
                                    15%
                                 
                                                             | 
                                                        
                    |
| 8 | 5 | 
                                                                 
                                    
                                    12.5%
                                 
                                                             | 
                                                        
                    |
| 9 | 1 | 
                                                                 
                                    
                                    2.5%
                                 
                                                             | 
                                                        
                    |
| 10 | Very effective | 5 | 
                                                                 
                                    
                                    12.5%
                                 
                                                             | 
                                                        
                    
| 11 | Don't know | 6 | 
                                                                 
                                    
                                    15%
                                 
                                                             |