| Value | Category | Cases | |
|---|---|---|---|
| -99 | 1 | 
                                    
                                    0.3%
                                 | |
| 1 | Not effective at all | 6 | 
                                    
                                    2%
                                 | 
| 2 | 9 | 
                                    
                                    3.1%
                                 | |
| 3 | 14 | 
                                    
                                    4.8%
                                 | |
| 4 | 16 | 
                                    
                                    5.5%
                                 | |
| 5 | 38 | 
                                    
                                    13%
                                 | |
| 6 | 28 | 
                                    
                                    9.6%
                                 | |
| 7 | 15 | 
                                    
                                    5.1%
                                 | |
| 8 | 18 | 
                                    
                                    6.1%
                                 | |
| 9 | 10 | 
                                    
                                    3.4%
                                 | |
| 10 | Very effective | 7 | 
                                    
                                    2.4%
                                 | 
| 11 | Don't know | 131 | 
                                    
                                    44.7%
                                 | 
| Sysmiss | 8 |