| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 | 
                                    
                                    1.6%
                                 | 
| 1 | Yes | 17 | 
                                    
                                    2.8%
                                 | 
| 2 | No | 585 | 
                                    
                                    95.6%
                                 |