| Value | Category | 
                                    
                    
                        | 1 | Insufficient information | 
                                    
                    
                        | 2 | Core/contact wasn't available | 
                                    
                    
                        | 3 | Unable to reach location | 
                                    
                    
                        | 8 | Don't know | 
                                    
                    
                        | 9 | Missing | 
                                    
                    
                        | 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.