| Value | Category | 
                                    
                    
                        | 0 | no flag | 
                                    
                    
                        | 1 | > interval | 
                                    
                    
                        | 2 | > interval by 1 mnth | 
                                    
                    
                        | 3 | > age at death | 
                                    
                    
                        | 4 | during preg in cal. | 
                                    
                    
                        | Sysmiss |  | 
                            
            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.