Third Country Nationals constitute 6.8% of the total population. Many of them are concentrated in large cities, mainly Athens and Thessaloniki. There are no official data on minorities, but they are estimated between 300 to 500 thousand persons. Student population is increasingly diverse, particularly at primary and secondary level. The fee for one year residence permit is 150€, for Long-term residence permit 600€, for Indefinite duration 900€, and for naturalisation 700€.