| Value | 
                    Category | 
                                                                            
                                    
                    
                        | 0 | 
                        Less than primary  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 1 | 
                        Less than primary, illiterate  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 2 | 
                        Less than primary, literate  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 10 | 
                        Primary  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 20 | 
                        Secondary  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 21 | 
                        Lower secondary (grades 4-8)  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 22 | 
                        Upper secondary (grades 9-10)  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 30 | 
                        Technical vocational, unspecified  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 31 | 
                        Post-primary technical  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 32 | 
                        Secondary or post-secondary technical  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 40 | 
                        Higher education  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 41 | 
                        Some higher education  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 42 | 
                        Completed higher education  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 99 | 
                        NIU (not in universe)  | 
                        
                            
                        
                        
                        
                        
                            
                    
                            
            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.