| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 1 | 
                                    
                                    0.1%
                                 | 
| 1 | Yes | 180 | 
                                    
                                    17.6%
                                 | 
| 2 | No | 843 | 
                                    
                                    82.3%
                                 |