| Value | Category | 
                                    
                    
                        | 1 | metal | 
                                    
                    
                        | 2 | tiles | 
                                    
                    
                        | 3 | shingles | 
                                    
                    
                        | 4 | thatch | 
                                    
                    
                        | 5 | plastic sheets | 
                                    
                    
                        | 6 | asbestos | 
                                    
                    
                        | 7 | multiple materials | 
                                    
                    
                        | 8 | could not tell | 
                            
            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.