| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 2 | 
                                    
                                    1.9%
                                 | 
| 2 | 2 | 
                                    
                                    1.9%
                                 | |
| 3 | 11 | 
                                    
                                    10.4%
                                 | |
| 4 | 6 | 
                                    
                                    5.7%
                                 | |
| 5 | 10 | 
                                    
                                    9.4%
                                 | |
| 6 | 8 | 
                                    
                                    7.5%
                                 | |
| 7 | 17 | 
                                    
                                    16%
                                 | |
| 8 | 19 | 
                                    
                                    17.9%
                                 | |
| 9 | 6 | 
                                    
                                    5.7%
                                 | |
| 10 | Very effective | 2 | 
                                    
                                    1.9%
                                 | 
| 11 | Don't know | 23 | 
                                    
                                    21.7%
                                 | 
| Sysmiss | 6 |