| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 19 | 
                                    
                                    1.3%
                                 | 
| 1 | Yes | 365 | 
                                    
                                    25.8%
                                 | 
| 2 | No | 1032 | 
                                    
                                    72.9%
                                 |