| Value | 
                    Category | 
                                                                            
                                    
                    
                        | 1 | 
                        12  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 2 | 
                        20  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 3 | 
                        25  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 4 | 
                        35  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 5 | 
                        45  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 6 | 
                        54  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 7 | 
                        65  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 8 | 
                        950  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 9 | 
                        1500  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 10 | 
                        2000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 11 | 
                        2500  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 12 | 
                        2600  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 13 | 
                        3000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 14 | 
                        3200  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 15 | 
                        3250  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 16 | 
                        3500  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 17 | 
                        3600  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 18 | 
                        3700  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 19 | 
                        3800  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 20 | 
                        4000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 21 | 
                        4500  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 22 | 
                        4800  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 23 | 
                        5000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 24 | 
                        6000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 25 | 
                        6500  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 26 | 
                        7000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 27 | 
                        7500  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 28 | 
                        8000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 29 | 
                        10000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 30 | 
                        15000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 31 | 
                        20000  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 32 | 
                        Don't know  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 33 | 
                        Refused to answer  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 34 | 
                        Outlier set to missing  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 35 | 
                        Inconsistency set to missing  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 36 | 
                        Not applicable  | 
                        
                            
                        
                        
                        
                        
                            
                    
                            
            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.