| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 0 | 
                                                                 
                                    
                                    0%
                                 
                                                             | 
                                                        
                    
| 0 | 2 | 
                                                                 
                                    
                                    10.5%
                                 
                                                             | 
                                                        
                    |
| 1 | 1 | 
                                                                 
                                    
                                    5.3%
                                 
                                                             | 
                                                        
                    |
| 10 | 1 | 
                                                                 
                                    
                                    5.3%
                                 
                                                             | 
                                                        
                    |
| 20 | 4 | 
                                                                 
                                    
                                    21.1%
                                 
                                                             | 
                                                        
                    |
| 30 | 7 | 
                                                                 
                                    
                                    36.8%
                                 
                                                             | 
                                                        
                    |
| 40 | 2 | 
                                                                 
                                    
                                    10.5%
                                 
                                                             | 
                                                        
                    |
| 50 | 2 | 
                                                                 
                                    
                                    10.5%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 356 |