| Value | Category | 
                                    
                    
                        | 1 | Observed | 
                                    
                    
                        | 2 | Not observed: not in dwelling | 
                                    
                    
                        | 3 | Not observed: no permission to see | 
                                    
                    
                        | 4 | Not observed: other reason | 
                            
            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.