| Value | Category | Cases | |
|---|---|---|---|
| -99 | 1 | 
                                    
                                    0.8%
                                 | |
| 1 | Not effective at all | 1 | 
                                    
                                    0.8%
                                 | 
| 2 | 3 | 
                                    
                                    2.3%
                                 | |
| 3 | 2 | 
                                    
                                    1.5%
                                 | |
| 4 | 6 | 
                                    
                                    4.5%
                                 | |
| 5 | 22 | 
                                    
                                    16.5%
                                 | |
| 6 | 9 | 
                                    
                                    6.8%
                                 | |
| 7 | 28 | 
                                    
                                    21.1%
                                 | |
| 8 | 18 | 
                                    
                                    13.5%
                                 | |
| 9 | 9 | 
                                    
                                    6.8%
                                 | |
| 10 | Very effective | 2 | 
                                    
                                    1.5%
                                 | 
| 11 | Don't know | 32 | 
                                    
                                    24.1%
                                 | 
| Sysmiss | 1 |