| Value | Category | 
                                    
                    
                        | 1 | Daily | 
                                    
                    
                        | 2 | 5-6 days per week | 
                                    
                    
                        | 3 | 3-4 days per week | 
                                    
                    
                        | 4 | 1-2 days per week | 
                                    
                    
                        | 5 | 1-3 days per month | 
                                    
                    
                        | 6 | Less than once a month | 
                                    
                    
                        | 7 | Never | 
                                    
                    
                        | 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.