| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                    
                                    0.4%
                                 | 
| 1 | Yes | 215 | 
                                    
                                    22.5%
                                 | 
| 2 | No | 736 | 
                                    
                                    77.1%
                                 |