| Value | Category | 
                                    
                    
                        | 1 | Not home during entire survey period | 
                                    
                    
                        | 2 | Too ill | 
                                    
                    
                        | 3 | handicapped or deformed | 
                                    
                    
                        | 4 | Not willing | 
                                    
                    
                        | 5 | Other | 
                                    
                    
                        | 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.