In the immediate aftermath of the Second World War, Germany was split into four zones, each administered by France, the United Kingdom, the United States and the Soviet Union respectively. In 1949, the Soviet-controlled zone formed the German Democratic Republic (East Germany), while the rest became the Federal Republic of Germany (West Germany). In this time, Berlin was also split into four zones, and the three non-Soviet zones formed West Berlin, which was a part of West Germany (although the West's administrative capital was moved to Bonn). One population grows, while the other declines Between 1949 and 1961, an estimated 2.7 million people migrated from East to West Germany. East Germany had a communist government with a socialist economy and was a satellite state of the Soviet Union, whereas West Germany was a liberal democracy with a capitalist economy, and western autonomy increased over time. Because of this difference, West Germany was a much freer society with more economic opportunities. During the German partition, the population of the west grew, from 51 million in 1950 to 62.7 million in 1989, whereas the population of East Germany declined from 18.4 million to just 16.4 million during this time. Little change after reunification In 1989, after four decades of separation, the process of German reunification began. The legal and physical barriers that had split the country were removed, and Germans could freely travel within the entire country. Despite this development, population growth patterns did not change. The population of the 'new states' (East Germany) continued to decline, whereas the population of the west grew, particularly in the 1990s, the first decade after reunification. The reasons for this continued imbalance between German population in the east and west, is mostly due to a low birth rate and internal migration within Germany. Despite the fact that levels of income and unemployment in the new states have gotten closer to those reported for the west (a major obstacle after reunification), life and opportunities in the west continue to attract young Germans from rural areas in the east with detrimental effect on the economy and demography of the new states.