| Value | Category | Cases | |
|---|---|---|---|
| -99 | 8 | 
                                    
                                    2.6%
                                 | |
| 1 | Not effective at all | 12 | 
                                    
                                    4%
                                 | 
| 2 | 12 | 
                                    
                                    4%
                                 | |
| 3 | 11 | 
                                    
                                    3.6%
                                 | |
| 4 | 28 | 
                                    
                                    9.2%
                                 | |
| 5 | 34 | 
                                    
                                    11.2%
                                 | |
| 6 | 19 | 
                                    
                                    6.3%
                                 | |
| 7 | 13 | 
                                    
                                    4.3%
                                 | |
| 8 | 15 | 
                                    
                                    5%
                                 | |
| 9 | 15 | 
                                    
                                    5%
                                 | |
| 10 | Very effective | 28 | 
                                    
                                    9.2%
                                 | 
| 11 | Don't know | 108 | 
                                    
                                    35.6%
                                 | 
| Sysmiss | 23 |