| Value | Category | 
                                    
                    
                        | 1 | PRIMARY ONLY | 
                                    
                    
                        | 2 | PRE- & PRIMARY | 
                                    
                    
                        | 3 | PRIMARY & SECONDARY | 
                                    
                    
                        | 4 | PRE-, PRIMARY & SECONDARY | 
                                    
                    
                        | 9 | omitted | 
                            
            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.