| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 212 | 
                                                                 
                                    
                                    39.6%
                                 
                                                             | 
                                                        
                    
| 2 | No | 322 | 
                                                                 
                                    
                                    60.2%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 983 |