| Value | Category | Cases | |
|---|---|---|---|
| -99 | 9 | 
                                    
                                    2.4%
                                 | |
| 1 | Not effective at all | 3 | 
                                    
                                    0.8%
                                 | 
| 2 | 1 | 
                                    
                                    0.3%
                                 | |
| 3 | 6 | 
                                    
                                    1.6%
                                 | |
| 4 | 11 | 
                                    
                                    2.9%
                                 | |
| 5 | 22 | 
                                    
                                    5.8%
                                 | |
| 6 | 31 | 
                                    
                                    8.2%
                                 | |
| 7 | 46 | 
                                    
                                    12.1%
                                 | |
| 8 | 49 | 
                                    
                                    12.9%
                                 | |
| 9 | 22 | 
                                    
                                    5.8%
                                 | |
| 10 | Very effective | 11 | 
                                    
                                    2.9%
                                 | 
| 11 | Don't know | 169 | 
                                    
                                    44.5%
                                 | 
| Sysmiss | 49 |