| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 25 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 2121 | 
                                                                 
                                    
                                    20.5%
                                 
                                                             | 
                                                        
                    
| 2 | No | 8197 | 
                                                                 
                                    
                                    79.3%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 329 |