| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    0.9%
                                 | 
| 1 | Yes | 33 | 
                                    
                                    29.5%
                                 | 
| 2 | No | 78 | 
                                    
                                    69.6%
                                 | 
| Sysmiss | 843 |