| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 10 | 
                                    
                                    4.2%
                                 | 
| 2 | 2 | 
                                    
                                    0.8%
                                 | |
| 3 | 3 | 
                                    
                                    1.3%
                                 | |
| 4 | 9 | 
                                    
                                    3.8%
                                 | |
| 5 | 13 | 
                                    
                                    5.5%
                                 | |
| 6 | 24 | 
                                    
                                    10.1%
                                 | |
| 7 | 42 | 
                                    
                                    17.7%
                                 | |
| 8 | 57 | 
                                    
                                    24.1%
                                 | |
| 9 | 50 | 
                                    
                                    21.1%
                                 | |
| 10 | Very effective | 27 | 
                                    
                                    11.4%
                                 | 
| 11 | Don't know | 150 | |
| Sysmiss | 34 |