| Value | 
                    Category | 
                                                                            
                                    
                    
                        | 0 | 
                        NIU (not in universe)  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 10 | 
                        Primary education  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 20 | 
                        Compulsory (lower) secondary school  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 30 | 
                        Upper secondary education  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 31 | 
                        Higher general secondary  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 32 | 
                        Higher technical and vocational secondary school  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 33 | 
                        Intermediate technical and vocational school  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 34 | 
                        Apprenticeship training  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 40 | 
                        Non-university education  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 41 | 
                        Technical or vocational course  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 42 | 
                        (Academic) Intermediate degrees  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 50 | 
                        University, college  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 60 | 
                        Doctorate  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 99 | 
                        Unknown  | 
                        
                            
                        
                        
                        
                        
                            
                    
                            
            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.