| Value | Category | Cases | |
|---|---|---|---|
| -99 | 1 | 
                                    
                                    0.3%
                                 | |
| 1 | Not effective at all | 17 | 
                                    
                                    5.7%
                                 | 
| 2 | 21 | 
                                    
                                    7%
                                 | |
| 3 | 23 | 
                                    
                                    7.7%
                                 | |
| 4 | 21 | 
                                    
                                    7%
                                 | |
| 5 | 28 | 
                                    
                                    9.4%
                                 | |
| 6 | 20 | 
                                    
                                    6.7%
                                 | |
| 7 | 21 | 
                                    
                                    7%
                                 | |
| 8 | 16 | 
                                    
                                    5.4%
                                 | |
| 9 | 10 | 
                                    
                                    3.3%
                                 | |
| 10 | Very effective | 24 | 
                                    
                                    8%
                                 | 
| 11 | Don't know | 97 | 
                                    
                                    32.4%
                                 | 
| Sysmiss | 27 |