| Value | Category | 
                                    
                    
                        | 0 | 0. Never/Grade 0 | 
                                    
                    
                        | 1 | 1. Grade 1/Sub A | 
                                    
                    
                        | 2 | 2. Grade 2/Sub B | 
                                    
                    
                        | 3 | 3. Grade 3/Standard 1 | 
                                    
                    
                        | 4 | 4. Grade 4/Standard 2 | 
                                    
                    
                        | 5 | 5. Grade 5/Standard 3 | 
                                    
                    
                        | 6 | 6. Grade 6/Standard 4 | 
                                    
                    
                        | 7 | 7. Grade 7/Standard 5 | 
                                    
                    
                        | 8 | 8. Grade 8/Standard 6 | 
                                    
                    
                        | 9 | 9. Grade 9/Standard 7 | 
                                    
                    
                        | 10 | 10. Grade 10/Standard 8 | 
                                    
                    
                        | 11 | 11. Grade 11/Standard 9 | 
                                    
                    
                        | 12 | 12. Grade 12/Standard 10/Matric | 
                                    
                    
                        | 13 | 13. NTC I | 
                                    
                    
                        | 14 | 14. NTC II | 
                                    
                    
                        | 15 | 15. NTC III | 
                                    
                    
                        | 16 | 16. Technikon | 
                                    
                    
                        | 17 | 17. University | 
                                    
                    
                        | 18 | 18. Other institution (not tech. | 
                                    
                    
                        | 19 | 19. Other | 
                                    
                    
                        | 20 | 20. Don't know | 
                            
            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.