| Value | Category | Cases | |
|---|---|---|---|
| -9 | Don't know (spontaneous) | 8 | 
                                                                 
                                    
                                    2.4%
                                 
                                                             | 
                                                        
                    
| -4 | Too many to count | 275 | 
                                                                 
                                    
                                    83.6%
                                 
                                                             | 
                                                        
                    
| 0 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 1 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 2 | 4 | 
                                                                 
                                    
                                    1.2%
                                 
                                                             | 
                                                        
                    |
| 3 | 16 | 
                                                                 
                                    
                                    4.9%
                                 
                                                             | 
                                                        
                    |
| 4 | 10 | 
                                                                 
                                    
                                    3%
                                 
                                                             | 
                                                        
                    |
| 5 | 5 | 
                                                                 
                                    
                                    1.5%
                                 
                                                             | 
                                                        
                    |
| 7 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 10 | 2 | 
                                                                 
                                    
                                    0.6%
                                 
                                                             | 
                                                        
                    |
| 15 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 20 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 30 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| 70 | 1 | 
                                                                 
                                    
                                    0.3%
                                 
                                                             | 
                                                        
                    |
| Sysmiss | 35 |