that their teaching equal that of the municipal schools. The Ministry of Education confers on private schools the right to use the final examinations of the folkeskole, thereby exercising a certain extent of quality control. In principle, however, it is not up to any government authority but to the parents of each private school to check that its performance measures up to the demands set for the municipal schools. The parents must themselves choose a supervisor to check the pupils' level of achievement in Danish, arithmetic, mathematics, and English. If the school is found inadequate, the supervisor must report it to the municipal school authority. In extraordinary circumstances, the Ministry of Education may establish special supervision, for example if there is reason to believe that the school teaches a subject so poorly that it may give the pupils problems later on in life. Educational experts say the rise in use of private schools in the 2000s is partly due to white Danish families putting their children in private schools when the neighbouring public school gets more than 30% pupils of immigrant background. About 24% of pupils grade 1-3 in Copenhagen attend private schools. Another factor is parents in small communities who have organized to start a private school when small public schools have closed as a results of the Danish municipality reform which led to fewer municipalities. Levels and age groups The folkeskole consists of an obligatory pre-school class, the 9-year obligatory course and a voluntary 11th year. It thus caters for pupils aged 6 to 17. The comprehensive concept of the folkeskole enables students to remain in the same student group with the same classmates from the 1st to the 10th (or 11th) form, sharing the same experiences in all subjects with peers of all types of backgrounds and covering the whole range of ability. The new act, which came into effect for the school year 1994-95, has abolished the division of the subjects of arithmetic, mathematics, English, German, physics, and chemistry into basic and advanced level courses in the 8th to 10th forms, introducing a system of differentiated teaching, by which the teachers have to adapt their teaching to the prerequisites of the individual pupil. General objectives Section 1 of the Act of the Folkeskole of 1994 states that: "The folkeskole shall — in co-operation with the parents — further the pupils' acquisition of knowledge, skills, working methods