hampered because it was unprotected and freely available to overseas competitors, encouraged by occupation authorities to access all records and facilities. Marshall Plan Thousands of the best German researchers and engineers were working in the Soviet Union and in the United States. The Marshall Plan was only extended to Western Germany after it was realized the suppression of its economy was holding back the recovery of other European countries and was not the main force behind the Wirtschaftswunder. However, it likely greatly contributed to Germany's overall economic recovery. Furthermore, often overlooked is the effect of the "unofficial contributions" of 150,000 U.S. occupation troops, earning as much as 4 Deutschmark to the dollar. These marks were spent within West Germany to buy food, luxury items, beer and cars, as well as entertaining the locals and for prostitutes. During exercises such numbers of soldiers would swell to over 250,000. Nonetheless, the amount of monetary aid, which was mainly in the form of loans, about $1.4 billion, was greatly overshadowed by the amount the Germans had to pay back as war reparations and by the charges the Allies made on the Germans for the ongoing cost of the occupation, about $2.4 billion per year. In 1953 it was decided that Germany would repay $1.1 billion of the aid it had received. The last repayment was made in June 1971. The demands of the Korean War in 1950–53 led to a global shortage of goods that helped overcome lingering resistance to the purchase of West German products. At the time West Germany had a large pool of skilled labour, partly as a result of the deportations and migrations which involved up to 16.5 million Germans. This helped West Germany to more than double the value of its exports during and shortly after the war. Apart from these factors, hard work and long hours at full capacity among the population in the 1950s, 1960s and early 1970s and extra labour supplied by thousands of Gastarbeiter ("guest workers", since the late 1950s) provided a vital base for the sustainment of the economic upturn with additional workforce. From the late 1950s, West Germany had one of the world's strongest economies. The East German economy also showed strong growth, but not as much as in West Germany, due to the bureaucratic system, emigration of working-age East Germans to West Germany and reparations to the USSR in terms of