| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 | 
                                    
                                    0.7%
                                 | 
| -7 | Does not apply (spontaneous) | 22 | 
                                    
                                    5.5%
                                 | 
| 1 | Yes | 76 | 
                                    
                                    19%
                                 | 
| 2 | No | 300 | 
                                    
                                    74.8%
                                 | 
| Sysmiss | 554 |