| Value | Category | Cases | |
|---|---|---|---|
| 1 | Not effective at all | 1 | 
                                    
                                    1.3%
                                 | 
| 2 | 2 | 
                                    
                                    2.5%
                                 | |
| 3 | 2 | 
                                    
                                    2.5%
                                 | |
| 4 | 5 | 
                                    
                                    6.3%
                                 | |
| 5 | 14 | 
                                    
                                    17.5%
                                 | |
| 6 | 8 | 
                                    
                                    10%
                                 | |
| 7 | 17 | 
                                    
                                    21.3%
                                 | |
| 8 | 20 | 
                                    
                                    25%
                                 | |
| 9 | 8 | 
                                    
                                    10%
                                 | |
| 10 | Very effective | 3 | 
                                    
                                    3.8%
                                 | 
| -99 | 6 | ||
| 11 | Don't know | 49 | |
| Sysmiss | 24 |