| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 4 | 
                                    
                                    57.1%
                                 | 
| -8 | Refusal (spontaneous) | 3 | 
                                    
                                    42.9%
                                 | 
| Sysmiss | 168 |