was "more than 4 million people of Turkish origin" in Germany; this has also been reiterated by other scholars. However, Michael Murphy Andregg said that by the 2000s "Germany was home to at least five million Turks"; various scholars have also given this estimate. Jytte Klausen cited German statistics in 2005 showing 2.4 million Turks, but acknowledged that unlike Catholics, Protestants, and Jews, the Turkish community cannot allocate their ethnic or religious identity in official counts. Indeed, a 2007 study by Clifford Geertz claimed that there was already "two million Turks in Berlin" alone. A higher estimate of 7 million Turks was given by Paul Gottfried in 2003, and Tessa Szyszkowitz quoted a senior European official who also said there was seven million Turks living in Germany in 2005. As of 2020, numerous scholars have estimated that there are approximately 7 million Turks in Germany, including Graham E. Fuller, James G. Lacey, Daniela Coli, and George K. Zestos and Rachel N. Cooke. Non-academic reports published by The Times, the Foundation for Subsidiarity, and Marianne have also suggested this figure. Settlements The Turkish community in Germany is concentrated predominantly in urban centers. The vast majority are found in the former West Germany, particularly in industrial regions such as the states of North Rhine-Westphalia (where a third of Turkish Germans live), and Baden-Württemberg and the working-class neighbourhoods of cities like Berlin, Hamburg, Bremen, Bochum, Bonn, Cologne, Dortmund, Duisburg, Düsseldorf, Essen, Frankfurt, Hanover, Heidelberg, Mannheim, Mainz, Nuremberg, Munich, Stuttgart, Aachen and Wiesbaden. Among the German districts in 2011, Duisburg, Gelsenkirchen, Heilbronn, Herne and Ludwigshafen had the highest shares of migrants from Turkey according to census data. Return migration In regards to return-migration, many Turkish nationals and Turkish Germans have also migrated from Germany to Turkey, for retirement or professional reasons. Official German records show that there are 2.8 million "returnees"; however, the German Embassy in Ankara estimates the true number to be four million, acknowledging the differences in German official data and the realities of the under-reporting by migrants. Integration Turkish immigrants make up Germany's largest immigrant group and have been ranked last in Berlin Institute's integration ranking. During a speech in Düsseldorf in 2011, Turkish Prime Minister Recep Tayyip Erdoğan urged Turks in Germany to integrate, but not assimilate, a statement that caused a political outcry in Germany. Citizenship For decades Turkish citizens in Germany were unable to become German citizens because