| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| 7 | 1 | 
                                    
                                    12.5%
                                 | |
| 15 | 1 | 
                                    
                                    12.5%
                                 | |
| 30 | 3 | 
                                    
                                    37.5%
                                 | |
| 45 | 1 | 
                                    
                                    12.5%
                                 | |
| 60 | 1 | 
                                    
                                    12.5%
                                 | |
| 75 | 1 | 
                                    
                                    12.5%
                                 | |
| Sysmiss | 303 |