| Value | Category | 
                                    
                    
                        | 1 | 1. COMPLETE, NO QUESTIONNAIRE ERRORS | 
                                    
                    
                        | 2 | 2. COMPLETE, WITH QUESTIONNAIRE ERRORS | 
                                    
                    
                        | 3 | 3. NOT COMPLETE | 
                                    
                    
                        | 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.