| Value | Category | 
                                    
                    
                        | 1 | yes, always or almost always | 
                                    
                    
                        | 2 | yes, sometimes | 
                                    
                    
                        | 3 | no, never or almost never | 
                                    
                    
                        | 4 |  | 
                                    
                    
                        | 8 | not applicable | 
                                    
                    
                        | 9 | don't know | 
                                    
                    
                        | 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.