both West Germany and East Germany radically amended their respective constitutions in accordance with that Treaty's provisions. East Germany then dissolved itself, and its five post-war states () were reconstituted, along with the reunited Berlin which ended its special status and formed an additional . They formally joined the Federal Republic on 3 October 1990, raising the number of states from 10 to 16, ending the division of Germany. The expanded Federal Republic retained West Germany's political culture and continued its existing memberships in international organisations, as well as its Western foreign policy alignment and affiliation to Western alliances like NATO and the European Union. The official German reunification ceremony on 3 October 1990 was held at the building, including Chancellor Helmut Kohl, President Richard von Weizsäcker, former Chancellor Willy Brandt and many others. One day later, the parliament of the united Germany would assemble in an act of symbolism in the Reichstag building. However, at that time, the role of Berlin had not yet been decided upon. Only after a fierce debate, considered by many as one of the most memorable sessions of parliament, the concluded on 20 June 1991, with quite a slim majority, that both government and parliament should move to Berlin from Bonn. Economic miracle The West German ("economic miracle", coined by The Times) began in 1950. This improvement was sustained by the currency reform of 1948 which replaced the with the and halted rampant inflation. The Allied dismantling of the West German coal and steel industry finally ended in 1950. As demand for consumer goods increased after World War II, the resulting shortage helped overcome lingering resistance to the purchase of German products. At the time Germany had a large pool of skilled and cheap labour, partly as a result of the flight and expulsion of Germans from Central and Eastern Europe, which affected up to 16.5 million Germans. This helped Germany to more than double the value of its exports during the war. Apart from these factors, hard work and long hours at full capacity among the population and in the late 1950s and 1960s extra labour supplied by thousands of ("guest workers") provided a vital base for the economic upturn. This would have implications later on for successive German governments as they tried to assimilate this group of workers. With the dropping of Allied reparations, the freeing of German intellectual property and the