| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 30 | 
                                    
                                    4%
                                 | 
| 1 | Yes | 179 | 
                                    
                                    24.2%
                                 | 
| 2 | No | 532 | 
                                    
                                    71.8%
                                 | 
| Sysmiss | 675 |