| Value | Category | 
                                    
                    
                        | 1 | cardboard/plastic/canvas | 
                                    
                    
                        | 2 | grass thatch and mud | 
                                    
                    
                        | 3 | metal/asbestos | 
                                    
                    
                        | 4 | cement/concrete | 
                                    
                    
                        | 5 | tile | 
                            
            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.