Greeks have been very mobile throughout their history. Areas of population concentration have shifted, and villages have come and gone with transitions from one period to another. Since establishment of the Greek nation, there has been much movement from upland, interior villages to lowland and coastal ones. Hundreds of new villages have been founded in the process. There has also been increasing migration from all villages to a few large cities. Greece became over 50 percent urbanized in the late 1960s. Metropolitan Athens now houses nearly one-third of the national population. Villages, which now average 500 inhabitants, can be compact clusters around a central square, linear strings along a road, or even sometimes scattered housing dispersed over a region. Market towns, ranging between 1,000 and 10,000 residents, are intermediaries between various regions and such major cities as greater Athens, Thessaloniki, Patras, Iraklion, and Volos.