| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 2 | 
                                    
                                    2.5%
                                 | 
| 3 | 1 | 
                                    
                                    1.3%
                                 | |
| 4 | 1 | 
                                    
                                    1.3%
                                 | |
| 5 | 15 | 
                                    
                                    19%
                                 | |
| 6 | 10 | 
                                    
                                    12.7%
                                 | |
| 7 | 10 | 
                                    
                                    12.7%
                                 | |
| 8 | 12 | 
                                    
                                    15.2%
                                 | |
| 9 | 7 | 
                                    
                                    8.9%
                                 | |
| 10 | Very effective | 11 | 
                                    
                                    13.9%
                                 | 
| 11 | Don't know | 10 | 
                                    
                                    12.7%
                                 | 
| Sysmiss | 5 |