| Value | Category | 
                                    
                    
                        | 1 | None | 
                                    
                    
                        | 2 | Primary | 
                                    
                    
                        | 3 | Basic (lower secondary) | 
                                    
                    
                        | 4 | Upper secondary | 
                                    
                    
                        | 5 | Vocational | 
                                    
                    
                        | 6 | College, university | 
                                    
                    
                        | 9 | Missing/DK | 
                            
            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.