| Value | Category | Cases | |
|---|---|---|---|
| -99 | 12 | 
                                    
                                    3.2%
                                 | |
| 1 | Not effective at all | 2 | 
                                    
                                    0.5%
                                 | 
| 2 | 3 | 
                                    
                                    0.8%
                                 | |
| 3 | 4 | 
                                    
                                    1.1%
                                 | |
| 4 | 7 | 
                                    
                                    1.8%
                                 | |
| 5 | 22 | 
                                    
                                    5.8%
                                 | |
| 6 | 33 | 
                                    
                                    8.7%
                                 | |
| 7 | 54 | 
                                    
                                    14.2%
                                 | |
| 8 | 64 | 
                                    
                                    16.8%
                                 | |
| 9 | 29 | 
                                    
                                    7.6%
                                 | |
| 10 | Very effective | 15 | 
                                    
                                    3.9%
                                 | 
| 11 | Don't know | 135 | 
                                    
                                    35.5%
                                 | 
| Sysmiss | 49 |