| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 10 | 
                                    
                                    2.2%
                                 | 
| 1 | Yes | 142 | 
                                    
                                    31.3%
                                 | 
| 2 | No | 302 | 
                                    
                                    66.5%
                                 | 
| Sysmiss | 158 |