| Value | 
                    Category | 
                                                                            
                                    
                    
                        | -5 | 
                        other  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | -4 | 
                        missing data  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | -3 | 
                        refused to answer  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | -2 | 
                        not applicable  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | -1 | 
                        do not know  | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 0 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 15 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 20 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 40 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 50 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 60 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 80 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 100 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 150 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 200 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 250 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 300 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 400 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 500 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 700 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 950 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                                    
                    
                        | 1000 | 
                          | 
                        
                            
                        
                        
                        
                        
                            
                    
                            
            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.