| Value | Category | 
                                    
                    
                        | 0 | No education | 
                                    
                    
                        | 1 | Primary | 
                                    
                    
                        | 2 | Secondary - old system | 
                                    
                    
                        | 3 | Secondary - new system | 
                                    
                    
                        | 4 | Higher | 
                                    
                    
                        | 5 | Preschool | 
                                    
                    
                        | 8 | Don't know | 
                            
            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.