Education in Denmark is compulsory () for children below the age of 15 or 16, even though it is not compulsory to attend Folkeskole ("public school"). The school years up to the age of fifteen/sixteen are known as Folkeskole, since any education has to match the level offered there. About 82% of young people take further education in addition to this. Government-funded education is usually free of charge and open to all. Denmark has a tradition of private schools and about 15.6% of all children at basic school level attend private schools, which are supported by a voucher system. The Education Index, published with the UN's Human Development Index in 2008, based on data from 2013, lists Denmark as 0.873, amongst the highest in the world, beneath Australia, Finland and New Zealand. Literacy in Denmark is approximately 99% for both men and women. History The Danish education system has its origin in the cathedral- and monastery schools established by the Roman Catholic Church in the early Middle Ages, and seven of the schools established in the 12th and 13th centuries still exist today. After the Reformation, which was officially implemented in 1536, the schools were taken over by the Crown. Their main purpose was to prepare the students for theological studies by teaching them to read, write and speak Latin and Greek. Popular elementary education was at that time still very primitive, but in 1721, 240 rytterskoler ("cavalry schools") were established throughout the kingdom. Moreover, the religious movement of Pietism, spreading in the 18th century, required some level of literacy, thereby promoting the need for public education. The philanthropic thoughts of such people as Rousseau also helped spur developments in education open to all children. In 1809, the old Clergyman's School was transformed in accordance with the spirit of the time into a humanistic Civil Servant's School which was to "foster true humanity" through immersion in the ancient Greek and Latin cultures combined with some teaching of natural science and modern languages. Throughout the 19th century (and even up until today), the Danish education system was especially influenced by the ideas of clergyman, politician and poet N. F. S. Grundtvig, who advocated inspiring methods of teaching and the foundation of folk high schools. In 1871, the scientific and technical development of the 19th century led to a division of the secondary education into two lines: the languages and the mathematics-science