| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                    
                                    33.3%
                                 | 
| 0 | 6 | 
                                    
                                    50%
                                 | |
| 1 | 1 | 
                                    
                                    8.3%
                                 | |
| 80 | 1 | 
                                    
                                    8.3%
                                 | |
| Sysmiss | 99 |