Responsibility for educational supervision in Germany is primarily organised within the individual states. Optional kindergarten education is provided for all children between three and six years old, after which school attendance is compulsory for at least nine years. Primary education usually lasts for four to six years. Secondary schooling is divided into tracks based on whether students pursue academic or vocational education. A system of apprenticeship called  leads to a skilled qualification which is almost comparable to an academic degree. It allows students in vocational training to learn in a company as well as in a state-run trade school. This model is well regarded and reproduced all around the world.