| Value | Category | Cases | |
|---|---|---|---|
| -99 | 6 | 
                                    
                                    2%
                                 | |
| 1 | Not effective at all | 15 | 
                                    
                                    4.9%
                                 | 
| 2 | 19 | 
                                    
                                    6.2%
                                 | |
| 3 | 24 | 
                                    
                                    7.8%
                                 | |
| 4 | 19 | 
                                    
                                    6.2%
                                 | |
| 5 | 23 | 
                                    
                                    7.5%
                                 | |
| 6 | 23 | 
                                    
                                    7.5%
                                 | |
| 7 | 20 | 
                                    
                                    6.5%
                                 | |
| 8 | 12 | 
                                    
                                    3.9%
                                 | |
| 9 | 15 | 
                                    
                                    4.9%
                                 | |
| 10 | Very effective | 27 | 
                                    
                                    8.8%
                                 | 
| 11 | Don't know | 104 | 
                                    
                                    33.9%
                                 | 
| Sysmiss | 19 |