| Value | Category | 
                                    
                    
                        | 1 | No storey | 
                                    
                    
                        | 2 | 1 storey, building on 2 levels | 
                                    
                    
                        | 3 | 2 or more storeyes,building on 3 or more | 
                                    
                    
                        | 4 | other types | 
                                    
                    
                        | 99 | Not stated | 
                            
            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.