| Value | Category | Cases | |
|---|---|---|---|
| -99 | 2 | 
                                    
                                    1.5%
                                 | |
| 1 | Not effective at all | 2 | 
                                    
                                    1.5%
                                 | 
| 2 | 4 | 
                                    
                                    3%
                                 | |
| 3 | 8 | 
                                    
                                    6%
                                 | |
| 4 | 4 | 
                                    
                                    3%
                                 | |
| 5 | 14 | 
                                    
                                    10.5%
                                 | |
| 6 | 9 | 
                                    
                                    6.8%
                                 | |
| 7 | 23 | 
                                    
                                    17.3%
                                 | |
| 8 | 15 | 
                                    
                                    11.3%
                                 | |
| 9 | 3 | 
                                    
                                    2.3%
                                 | |
| 10 | Very effective | 2 | 
                                    
                                    1.5%
                                 | 
| 11 | Don't know | 47 | 
                                    
                                    35.3%
                                 | 
| Sysmiss | 1 |