| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 7 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    
| 0 | None | 214 | 
                                                                 
                                    
                                    69.3%
                                 
                                                             | 
                                                        
                    
| 1 | 35 | 
                                                                 
                                    
                                    11.3%
                                 
                                                             | 
                                                        
                    |
| 2 | 17 | 
                                                                 
                                    
                                    5.5%
                                 
                                                             | 
                                                        
                    |
| 3 | 7 | 
                                                                 
                                    
                                    2.3%
                                 
                                                             | 
                                                        
                    |
| 4 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 5 | 8 | 
                                                                 
                                    
                                    2.6%
                                 
                                                             | 
                                                        
                    |
| 7 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 8 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 10 | 5 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 15 | 5 | 
                                                                 
                                    
                                    1.6%
                                 
                                                             | 
                                                        
                    |
| 19 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 20 | 3 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 30 | 3 | 
                                                                 
                                    
                                    1%
                                 
                                                             | 
                                                        
                    |
| 40 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 55 |