| Value | Category | 
                                    
                    
                        | 1 | one month or less | 
                                    
                    
                        | 2 | 2 months | 
                                    
                    
                        | 3 | 3 months | 
                                    
                    
                        | 4 | 4 months | 
                                    
                    
                        | 5 | 5 months | 
                                    
                    
                        | 6 | 6 months | 
                                    
                    
                        | 7 | 7 months and more | 
                            
            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.