The Soviet Union achieved rough nuclear parity with the United States. From the beginning of the post-war period, Western Europe and Japan rapidly recovered from the destruction of World War II and sustained strong economic growth through the 1950s and 1960s, with per capita GDPs approaching those of the United States, while Eastern Bloc economies stagnated. China, Japan, and Western Europe; the increasing nationalism of the Third World, and the growing disunity within the communist alliance all augured a new multipolar international structure. Moreover, the 1973 world oil shock created a dramatic shift in the economic fortunes of the superpowers. The rapid increase in the price of oil devastated the U.S. economy leading to "stagflation" and slow growth.