| Value | Category | Cases | |
|---|---|---|---|
| -99 | 9 | 
                                    
                                    3%
                                 | |
| 1 | Not effective at all | 18 | 
                                    
                                    6%
                                 | 
| 2 | 18 | 
                                    
                                    6%
                                 | |
| 3 | 16 | 
                                    
                                    5.4%
                                 | |
| 4 | 11 | 
                                    
                                    3.7%
                                 | |
| 5 | 21 | 
                                    
                                    7%
                                 | |
| 6 | 17 | 
                                    
                                    5.7%
                                 | |
| 7 | 20 | 
                                    
                                    6.7%
                                 | |
| 8 | 19 | 
                                    
                                    6.4%
                                 | |
| 9 | 22 | 
                                    
                                    7.4%
                                 | |
| 10 | Very effective | 36 | 
                                    
                                    12.1%
                                 | 
| 11 | Don't know | 91 | 
                                    
                                    30.5%
                                 | 
| Sysmiss | 28 |