| Value | Category | 
                                    
                    
                        | 1 | 1=5 or more days a week | 
                                    
                    
                        | 2 | 2=1-4 days a week | 
                                    
                    
                        | 3 | 3=1-3 days a month | 
                                    
                    
                        | 4 | 4=less than once a month | 
                                    
                    
                        | 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.