| Value | Category | Cases | |
|---|---|---|---|
| -99 | 4 | 
                                    
                                    1%
                                 | |
| 1 | Not effective at all | 2 | 
                                    
                                    0.5%
                                 | 
| 2 | 1 | 
                                    
                                    0.3%
                                 | |
| 3 | 7 | 
                                    
                                    1.8%
                                 | |
| 4 | 6 | 
                                    
                                    1.6%
                                 | |
| 5 | 21 | 
                                    
                                    5.5%
                                 | |
| 6 | 33 | 
                                    
                                    8.6%
                                 | |
| 7 | 46 | 
                                    
                                    12%
                                 | |
| 8 | 59 | 
                                    
                                    15.4%
                                 | |
| 9 | 30 | 
                                    
                                    7.8%
                                 | |
| 10 | Very effective | 14 | 
                                    
                                    3.7%
                                 | 
| 11 | Don't know | 160 | 
                                    
                                    41.8%
                                 | 
| Sysmiss | 46 |