| Value | Category | 
                                    
                    
                        | 1 | Once a week | 
                                    
                    
                        | 2 | Once in 15 days | 
                                    
                    
                        | 3 | Once a month | 
                                    
                    
                        | 4 | Less than a month | 
                                    
                    
                        | 5 | Almost never | 
                                    
                    
                        | 8 | Don't know | 
                            
            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.