| Value | Category | 
                                    
                    
                        | 0 |  | 
                                    
                    
                        | 1 | Less than 30 minutes | 
                                    
                    
                        | 2 | 30 - 45 minutes | 
                                    
                    
                        | 3 | 45 - 60 minutes | 
                                    
                    
                        | 4 | More than 60 minutes | 
                                    
                    
                        | 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.