| Value | Category | 
                                    
                    
                        | 0 | None | 
                                    
                    
                        | 2014 |  | 
                                    
                    
                        | 2015 |  | 
                                    
                    
                        | 2016 |  | 
                                    
                    
                        | 4444 | Marked on card | 
                                    
                    
                        | 6666 | Mother reported | 
                                    
                    
                        | 9998 | DK | 
                                    
                    
                        | 9999 | 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.