| Value | Category | 
                                    
                    
                        | 1 | Grades 1-5 | 
                                    
                    
                        | 2 | Grades 1-8 | 
                                    
                    
                        | 3 | Grades 1-11 | 
                                    
                    
                        | 4 | Grades 1-13 | 
                                    
                    
                        | 5 | Grades 6-11 | 
                                    
                    
                        | 6 | Grades 6-13 | 
                            
            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.