| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 158 | 
                                                                 
                                    
                                    27.8%
                                 
                                                             | 
                                                        
                    
| 0 | 226 | 
                                                                 
                                    
                                    39.8%
                                 
                                                             | 
                                                        
                    |
| 1 | 161 | 
                                                                 
                                    
                                    28.3%
                                 
                                                             | 
                                                        
                    |
| 2 | 17 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    |
| 3 | 3 | 
                                                                 
                                    
                                    0.5%
                                 
                                                             | 
                                                        
                    |
| 4 | 1 | 
                                                                 
                                    
                                    0.2%
                                 
                                                             | 
                                                        
                    |
| 8 | 2 | 
                                                                 
                                    
                                    0.4%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 10104 |