| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 | 
                                                                 
                                    
                                    15.8%
                                 
                                                             | 
                                                        
                    
| 0 | 13 | 
                                                                 
                                    
                                    68.4%
                                 
                                                             | 
                                                        
                    |
| 10 | 1 | 
                                                                 
                                    
                                    5.3%
                                 
                                                             | 
                                                        
                    |
| 40 | 2 | 
                                                                 
                                    
                                    10.5%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 95 |