| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 | 
                                    
                                    0.7%
                                 | 
| 1 | Yes | 58 | 
                                    
                                    14.1%
                                 | 
| 2 | No | 349 | 
                                    
                                    85.1%
                                 | 
| Sysmiss | 545 |