| Value | Category | 
                                    
                    
                        | 1 | 1 month or less | 
                                    
                    
                        | 2 | 2-6 months | 
                                    
                    
                        | 3 | 7-12 months | 
                                    
                    
                        | 4 | More than a year | 
                                    
                    
                        | 97 | Other (specify) | 
                                    
                    
                        | 99 | Don't know/can't say | 
                                    
                    
                        | Sysmiss |  | 
                            
            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.