| Value | Category | 
                                    
                    
                        | 1 | 0 - 14 min | 
                                    
                    
                        | 2 | 15 - 29 min | 
                                    
                    
                        | 3 | 30 - 44 min | 
                                    
                    
                        | 4 | 45 - 59 min | 
                                    
                    
                        | 5 | 60 min or more | 
                                    
                    
                        | 6 | Don't know | 
                                    
                    
                        | 9 | Unspecified | 
                            
            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.