| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    0.4%
                                 | 
| 1 | Yes | 62 | 
                                    
                                    27.4%
                                 | 
| 2 | No | 163 | 
                                    
                                    72.1%
                                 | 
| Sysmiss | 138 |