| Value | Category | Cases | |
|---|---|---|---|
| -99 | 6 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    |
| 1 | Not effective at all | 6 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    
| 2 | 8 | 
                                                                 
                                    
                                    2%
                                 
                                                             | 
                                                        
                    |
| 3 | 6 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    |
| 4 | 16 | 
                                                                 
                                    
                                    4.1%
                                 
                                                             | 
                                                        
                    |
| 5 | 37 | 
                                                                 
                                    
                                    9.4%
                                 
                                                             | 
                                                        
                    |
| 6 | 30 | 
                                                                 
                                    
                                    7.6%
                                 
                                                             | 
                                                        
                    |
| 7 | 56 | 
                                                                 
                                    
                                    14.2%
                                 
                                                             | 
                                                        
                    |
| 8 | 49 | 
                                                                 
                                    
                                    12.4%
                                 
                                                             | 
                                                        
                    |
| 9 | 26 | 
                                                                 
                                    
                                    6.6%
                                 
                                                             | 
                                                        
                    |
| 10 | Very effective | 35 | 
                                                                 
                                    
                                    8.9%
                                 
                                                             | 
                                                        
                    
| 11 | Don't know | 120 | 
                                                                 
                                    
                                    30.4%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 12 |