| Value | Category | Cases | |
|---|---|---|---|
| -99 | 2 | 
                                    
                                    1.5%
                                 | |
| 1 | Not effective at all | 2 | 
                                    
                                    1.5%
                                 | 
| 2 | 2 | 
                                    
                                    1.5%
                                 | |
| 3 | 4 | 
                                    
                                    3%
                                 | |
| 4 | 10 | 
                                    
                                    7.5%
                                 | |
| 5 | 21 | 
                                    
                                    15.8%
                                 | |
| 6 | 22 | 
                                    
                                    16.5%
                                 | |
| 7 | 21 | 
                                    
                                    15.8%
                                 | |
| 8 | 11 | 
                                    
                                    8.3%
                                 | |
| 9 | 5 | 
                                    
                                    3.8%
                                 | |
| 10 | Very effective | 3 | 
                                    
                                    2.3%
                                 | 
| 11 | Don't know | 30 | 
                                    
                                    22.6%
                                 | 
| Sysmiss | 1 |