| Value | Category | 
                                    
                    
                        | 0 | Kindergarten | 
                                    
                    
                        | 1 | Alternative form of education | 
                                    
                    
                        | 2 | Secondary | 
                                    
                    
                        | 3 | Vocational training | 
                                    
                    
                        | 4 | Higher | 
                                    
                    
                        | 8 | DK | 
                                    
                    
                        | 9 | Missing | 
                                    
                    
                        | Sysmiss |  | 
                            
            Warning: these figures indicate the number of cases found in the data file. They cannot be interpreted as summary statistics of the population of interest.