| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 15 | 
                                                                 
                                    
                                    0.1%
                                 
                                                             | 
                                                        
                    
| 1 | Yes | 985 | 
                                                                 
                                    
                                    9.7%
                                 
                                                             | 
                                                        
                    
| 2 | No | 9104 | 
                                                                 
                                    
                                    90.1%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 568 |