| Value | Category | 
                                    
                    
                        | 0 |  | 
                                    
                    
                        | 1 | until 1 month | 
                                    
                    
                        | 2 | 1 to 3 month | 
                                    
                    
                        | 3 | 4 to 6 months | 
                                    
                    
                        | 4 | 7 to 12 months | 
                                    
                    
                        | 5 | more than 12 months | 
                            
            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.