| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    
| 2 | 3 | 
                                                                 
                                    
                                    0.9%
                                 
                                                             | 
                                                        
                    |
| 3 | 9 | 
                                                                 
                                    
                                    2.8%
                                 
                                                             | 
                                                        
                    |
| 4 | 12 | 
                                                                 
                                    
                                    3.7%
                                 
                                                             | 
                                                        
                    |
| 5 | 31 | 
                                                                 
                                    
                                    9.6%
                                 
                                                             | 
                                                        
                    |
| 6 | 57 | 
                                                                 
                                    
                                    17.7%
                                 
                                                             | 
                                                        
                    |
| 7 | 60 | 
                                                                 
                                    
                                    18.6%
                                 
                                                             | 
                                                        
                    |
| 8 | 79 | 
                                                                 
                                    
                                    24.5%
                                 
                                                             | 
                                                        
                    |
| 9 | 45 | 
                                                                 
                                    
                                    14%
                                 
                                                             | 
                                                        
                    |
| 10 | Very effective | 24 | 
                                                                 
                                    
                                    7.5%
                                 
                                                             | 
                                                        
                    
| -99 | 71 | ||
| 11 | Don't know | 108 | |
| Sysmiss | 156 |