| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    0.4%
                                 | 
| 1 | Yes | 226 | 
                                    
                                    93%
                                 | 
| 2 | No | 16 | 
                                    
                                    6.6%
                                 | 
| Sysmiss | 712 |