| Value | Category | 
                                    
                    
                        | 1 | observed at least 1 valid | 
                                    
                    
                        | 2 | observed, but none valid | 
                                    
                    
                        | 3 | reported available, not seen | 
                                    
                    
                        | 4 | not available today/don't know | 
                                    
                    
                        | 5 | never available | 
                            
            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.