 Attendance of Gymnasium had strongly increased in the second part of the 20th century to the majority of pupils in many areas.As a consequence, mainly pupils with rather low aptitudes remained for the non-selective "Hauptschule", traditionally the third main tier (and originally the main tier) of the German school system.Some German federal states have abolished the three-tier system in favour of a combination of Realschule and Hauptschule, starting about 1997.