| Value | Category | 
                                    
                    
                        | 1 | 1-st quarter (months 1-3) | 
                                    
                    
                        | 2 | 2-nd quarter (months 4-6) | 
                                    
                    
                        | 3 | 3-rd quarter (months 7-9) | 
                                    
                    
                        | 4 | 4-th quarter (months 10-12) | 
                            
            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.