| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 2 | 
                                    
                                    0.7%
                                 | 
| 2 | 4 | 
                                    
                                    1.4%
                                 | |
| 3 | 11 | 
                                    
                                    3.7%
                                 | |
| 4 | 18 | 
                                    
                                    6.1%
                                 | |
| 5 | 45 | 
                                    
                                    15.3%
                                 | |
| 6 | 41 | 
                                    
                                    13.9%
                                 | |
| 7 | 40 | 
                                    
                                    13.6%
                                 | |
| 8 | 29 | 
                                    
                                    9.8%
                                 | |
| 9 | 9 | 
                                    
                                    3.1%
                                 | |
| 10 | Very effective | 10 | 
                                    
                                    3.4%
                                 | 
| 11 | Don't know | 86 | 
                                    
                                    29.2%
                                 | 
| Sysmiss | 6 |