| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 | 
                                    
                                    0.5%
                                 | 
| 1 | Yes | 119 | 
                                    
                                    19.4%
                                 | 
| 2 | No | 490 | 
                                    
                                    80.1%
                                 |