Demographics of Turkey are available for the Kurdish population, because the Turkish government has outlawed ethnic or racial censuses. An estimate by the CIA World Factbook places their proportion of the population at approximately 18%. Another estimate, according to Ibrahim Sirkeci, an ethnic Turk, in his book "The Environment of Insecurity in Turkey and the Emigration of Turkish Kurds to Germany", based on the 1990 Turkish Census and 1993 Turkish Demographic Health Survey, is 17.8%. Other estimates include 15.7% of the population according to the newspaper "Milliyet", and 23% by Kurdologist David McDowall. The Minority Rights Group report of 1985 (by Martin Short
Population exchange between Greece and Turkey a legitimizing factor or a "safe criterion" in marking ethnic groups as Turkish or as Greek in the population exchange. As a result, the Greek-Turkish population exchange did exchange the Greek-Orthodox population of Anatolia, Turkey and the Muslim population of Greece. However, due to the heterogeneous nature of these former Ottoman lands, many other ethnic groups posed social and legal challenges to the terms of the agreement for years after its signing. Among these were the Protestant and Catholic Greeks, the Arabs, Albanians, Russians, Serbians, Romanians of the Greek Orthodox religion; the Albanian, Bulgarian, Greek Muslims of Macedonia and Epirus,