| Value | Category | Cases | |
|---|---|---|---|
| 1 | Month a year | 6012 | 
                                                                 
                                    
                                    31.8%
                                 
                                                             | 
                                                        
                    
| 8 | DK | 12889 | 
                                                                 
                                    
                                    68.2%
                                 
                                                             | 
                                                        
                    
| Sysmiss | 6043 |