1: None
2: Primary school (lower education, special education)
3: Lower vocational education (e.g. LTS, LHNO, LEAO, domestic training school)
4: Lower general secondary education (e.g. VMBO, ULO, MULO, MAVO)
5: Secondary vocational education (e.g. MTS, MEAO, MHNO)
6: Senior general secondary education (e.g. HBS, MMS, HAVO, VWO, gymnasium)
7: Higher professional education (e.g. HTS, HEAO, HHNO)
8: University
9: Other