| Value | Category | Cases | |
|---|---|---|---|
| -99 | 1 | 
                                    
                                    0.3%
                                 | |
| 1 | Not effective at all | 3 | 
                                    
                                    1%
                                 | 
| 2 | 6 | 
                                    
                                    2.1%
                                 | |
| 3 | 8 | 
                                    
                                    2.7%
                                 | |
| 4 | 13 | 
                                    
                                    4.5%
                                 | |
| 5 | 39 | 
                                    
                                    13.4%
                                 | |
| 6 | 33 | 
                                    
                                    11.3%
                                 | |
| 7 | 36 | 
                                    
                                    12.3%
                                 | |
| 8 | 30 | 
                                    
                                    10.3%
                                 | |
| 9 | 12 | 
                                    
                                    4.1%
                                 | |
| 10 | Very effective | 7 | 
                                    
                                    2.4%
                                 | 
| 11 | Don't know | 104 | 
                                    
                                    35.6%
                                 | 
| Sysmiss | 9 |