| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 24 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 2383 | 
                                                                 
                                    
                                    40.5%
                                 
                                                             | 
                                                        
                    
| 2 | No | 3470 | 
                                                                 
                                    
                                    59%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 4795 |