| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 152 | 
                                                                 
                                    
                                    1.4%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 1758 | 
                                                                 
                                    
                                    16.5%
                                 
                                                             | 
                                                        
                    
| 2 | No | 8762 | 
                                                                 
                                    
                                    82.1%
                                 
                                                             |