| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 549 | 
                                                                 
                                    
                                    5.1%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 2396 | 
                                                                 
                                    
                                    22.5%
                                 
                                                             | 
                                                        
                    
| 2 | No | 7727 | 
                                                                 
                                    
                                    72.4%
                                 
                                                             |