| Value | Category | 
                                    
                    
                        | 1 | never | 
                                    
                    
                        | 2 | annually | 
                                    
                    
                        | 3 | half-annually | 
                                    
                    
                        | 4 | quarterly | 
                                    
                    
                        | 5 | monthly | 
                                    
                    
                        | 6 | weekly | 
                                    
                    
                        | 7 | daily | 
                                    
                    
                        | 8 | hourly | 
                                    
                    
                        | 10 | other | 
                                    
                    
                        | 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.