| Value | Category | 
                                    
                    
                        | -999 | -999 | 
                                    
                    
                        | -888 | -888 | 
                                    
                    
                        | 1 | Yes, every day | 
                                    
                    
                        | 2 | Yes, at least once per week | 
                                    
                    
                        | 3 | Yes, at least once per month | 
                                    
                    
                        | 4 | Do not listen | 
                                    
                    
                        | 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.