| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 1 | 
                                    
                                    1%
                                 | 
| 2 | 3 | 
                                    
                                    2.9%
                                 | |
| 3 | 8 | 
                                    
                                    7.6%
                                 | |
| 4 | 6 | 
                                    
                                    5.7%
                                 | |
| 5 | 6 | 
                                    
                                    5.7%
                                 | |
| 6 | 12 | 
                                    
                                    11.4%
                                 | |
| 7 | 15 | 
                                    
                                    14.3%
                                 | |
| 8 | 10 | 
                                    
                                    9.5%
                                 | |
| 9 | 5 | 
                                    
                                    4.8%
                                 | |
| 10 | Very effective | 3 | 
                                    
                                    2.9%
                                 | 
| 11 | Don't know | 36 | 
                                    
                                    34.3%
                                 | 
| Sysmiss | 7 |