| Value | Category | Cases | |
|---|---|---|---|
| -99 | 10 | 
                                    
                                    2.6%
                                 | |
| 1 | Not effective at all | 2 | 
                                    
                                    0.5%
                                 | 
| 2 | 2 | 
                                    
                                    0.5%
                                 | |
| 3 | 3 | 
                                    
                                    0.8%
                                 | |
| 4 | 4 | 
                                    
                                    1.1%
                                 | |
| 5 | 25 | 
                                    
                                    6.6%
                                 | |
| 6 | 34 | 
                                    
                                    8.9%
                                 | |
| 7 | 51 | 
                                    
                                    13.4%
                                 | |
| 8 | 70 | 
                                    
                                    18.4%
                                 | |
| 9 | 21 | 
                                    
                                    5.5%
                                 | |
| 10 | Very effective | 8 | 
                                    
                                    2.1%
                                 | 
| 11 | Don't know | 150 | 
                                    
                                    39.5%
                                 | 
| Sysmiss | 49 |