| Value | Category | Cases | |
|---|---|---|---|
| -99 | 4 | 
                                    
                                    1%
                                 | |
| 1 | Not effective at all | 2 | 
                                    
                                    0.5%
                                 | 
| 2 | 2 | 
                                    
                                    0.5%
                                 | |
| 3 | 5 | 
                                    
                                    1.3%
                                 | |
| 4 | 5 | 
                                    
                                    1.3%
                                 | |
| 5 | 21 | 
                                    
                                    5.5%
                                 | |
| 6 | 37 | 
                                    
                                    9.7%
                                 | |
| 7 | 51 | 
                                    
                                    13.3%
                                 | |
| 8 | 63 | 
                                    
                                    16.4%
                                 | |
| 9 | 40 | 
                                    
                                    10.4%
                                 | |
| 10 | Very effective | 25 | 
                                    
                                    6.5%
                                 | 
| 11 | Don't know | 128 | 
                                    
                                    33.4%
                                 | 
| Sysmiss | 46 |