| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 3 | 
                                                                 
                                    
                                    10%
                                 
                                                             | 
                                                        
                    
| 0 | 2 | 
                                                                 
                                    
                                    6.7%
                                 
                                                             | 
                                                        
                    |
| 5 | 3 | 
                                                                 
                                    
                                    10%
                                 
                                                             | 
                                                        
                    |
| 20 | 3 | 
                                                                 
                                    
                                    10%
                                 
                                                             | 
                                                        
                    |
| 30 | 7 | 
                                                                 
                                    
                                    23.3%
                                 
                                                             | 
                                                        
                    |
| 35 | 2 | 
                                                                 
                                    
                                    6.7%
                                 
                                                             | 
                                                        
                    |
| 40 | 1 | 
                                                                 
                                    
                                    3.3%
                                 
                                                             | 
                                                        
                    |
| 45 | 9 | 
                                                                 
                                    
                                    30%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 334 |