According to the Framework Law (3549/2007), Public higher education "Highest Educational Institutions" (Ανώτατα Εκπαιδευτικά Ιδρύματα, Anótata Ekpaideytiká Idrýmata, "ΑΕΙ") consists of two parallel sectors:the University sector (Universities, Polytechnics, Fine Arts Schools, the Open University) and the Technological sector (Technological Education Institutions (TEI) and the School of Pedagogic and Technological Education). There are also State Non-University Tertiary Institutes offering vocationally oriented courses of shorter duration (2 to 3 years) which operate under the authority of other Ministries. Students are admitted to these Institutes according to their performance at national level examinations taking place after completion of the third grade of Lykeio. Additionally, students over twenty-two years old may be admitted to the Hellenic Open University through a form of lottery. The Capodistrian University of Athens is the oldest university in the eastern Mediterranean.
Examinations for Tertiary institutes are given at what grade level? (If the question is unanswerable, say "unanswerable")
third grade