| Value | Category | 
                                    
                    
                        | 1 | Day aft. period end | 
                                    
                    
                        | 2 | 5days aft.period beg | 
                                    
                    
                        | 3 | Day aft. 1st. packet | 
                                    
                    
                        | 4 | 7days aft.1st packet | 
                                    
                    
                        | 5 | Other | 
                            
            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.