| Value | Category | 
                                    
                    
                        | 1 | 1 day | 
                                    
                    
                        | 2 | 1 week | 
                                    
                    
                        | 3 | 1 month | 
                                    
                    
                        | 4 | 2 months | 
                                    
                    
                        | 5 | 3 months | 
                                    
                    
                        | 6 | 6 months | 
                                    
                    
                        | 99 | N/R | 
                                    
                    
                        | 888 | Don't know | 
                                    
                    
                        | 999 | N/A | 
                            
            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.