| Value | Category | 
                                    
                    
                        | 1 | Upper | 
                                    
                    
                        | 2 | Upper middle | 
                                    
                    
                        | 3 | Middle middle | 
                                    
                    
                        | 4 | Lower middle | 
                                    
                    
                        | 5 | Working | 
                                    
                    
                        | 6 | Poor | 
                                    
                    
                        | 7 | Don't know | 
                                    
                    
                        | Sysmiss |  | 
                            
            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.