| Value | Category | 
                                    
                    
                        | -9 | missing | 
                                    
                    
                        | -8 | dk | 
                                    
                    
                        | -7 | na | 
                                    
                    
                        | 1 | never or rarely | 
                                    
                    
                        | 2 | some of the time | 
                                    
                    
                        | 3 | most of the time | 
                                    
                    
                        | 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.