| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 40 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 8204 | 
                                                                 
                                    
                                    89.6%
                                 
                                                             | 
                                                        
                    
| 2 | No | 916 | 
                                                                 
                                    
                                    10%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 1512 |