| Value | Category | 
                                    
                    
                        | 1 | Hour | 
                                    
                    
                        | 2 | Day | 
                                    
                    
                        | 3 | Week | 
                                    
                    
                        | 4 | Fortnight | 
                                    
                    
                        | 5 | Month | 
                                    
                    
                        | 6 | Quarter a year | 
                                    
                    
                        | 7 | Half a year | 
                                    
                    
                        | 8 | Annual | 
                                    
                    
                        | 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.