| Value | Category | 
                                    
                    
                        | 1 | completed primary or less | 
                                    
                    
                        | 2 | secondary | 
                                    
                    
                        | 3 | completed tertiary or more | 
                                    
                    
                        | 4 | (dk) | 
                                    
                    
                        | 5 | (rf) | 
                            
            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.