| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    0.6%
                                 | 
| 1 | Yes | 42 | 
                                    
                                    26.1%
                                 | 
| 2 | No | 118 | 
                                    
                                    73.3%
                                 | 
| Sysmiss | 1255 |