| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 25 | 
                                                                 
                                    
                                    46.3%
                                 
                                                             | 
                                                        
                    
| 3 | 1 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 5 | 1 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| 10 | 3 | 
                                                                 
                                    
                                    5.6%
                                 
                                                             | 
                                                        
                    |
| 15 | 9 | 
                                                                 
                                    
                                    16.7%
                                 
                                                             | 
                                                        
                    |
| 20 | 14 | 
                                                                 
                                    
                                    25.9%
                                 
                                                             | 
                                                        
                    |
| 25 | 1 | 
                                                                 
                                    
                                    1.9%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 334 |