The educational system in Croatia has four levels: early childhood education, elementary education, secondary education, and higher education. Elementary education is compulsory from ages 6.5 to 15 and includes 8 years of primary school. Secondary education is optional but most students attend gymnasiums (high schools), vocational schools, or art schools for another 4 years. Higher education includes polytechnic schools (higher education) and universities (highest level education) offering bachelor's, master's and doctoral degrees. Teachers are required to participate in ongoing professional development and can be promoted to teacher-mentor or teacher-counselor levels. The average monthly salary for primary education teachers is 6,221 kuna. Croatia is currently reforming