| Value | Category | Cases | |
|---|---|---|---|
| -99 | Don't know | 0 | 
                                    
                                    0%
                                 | 
| -9 | Don't know (spontaneous) | 0 | 
                                    
                                    0%
                                 | 
| 20 | 1 | 
                                    
                                    12.5%
                                 | |
| 25 | 1 | 
                                    
                                    12.5%
                                 | |
| 35 | 1 | 
                                    
                                    12.5%
                                 | |
| 40 | 3 | 
                                    
                                    37.5%
                                 | |
| 55 | 1 | 
                                    
                                    12.5%
                                 | |
| 60 | 1 | 
                                    
                                    12.5%
                                 | |
| Sysmiss | 352 |