Tariffs and Trade (GATT) led to a series of agreements to remove trade restrictions. GATT's successor was the World Trade Organization (WTO), which provided a framework for negotiating and formalizing trade agreements and a dispute resolution process. Exports nearly doubled from 8.5% of total gross world product in 1970 to 16.2% in 2001. The approach of using global agreements to advance trade stumbled with the failure of the Doha Development Round of trade negotiation. Many countries then shifted to bilateral or smaller multilateral agreements, such as the 2011 South Korea–United States Free Trade Agreement. Since the 1970s, aviation has become increasingly affordable to middle classes in developed countries. Open skies policies and low-cost carriers have helped to bring competition to the market. In the 1990s, the growth of low-cost communication networks cut the cost of communicating between countries. More work can be performed using a computer without regard to location. This included accounting, software development, and engineering design. Student exchange programs became popular after World War II, and are intended to increase the participants' understanding and tolerance of other cultures, as well as improving their language skills and broadening their social horizons. Between 1963 and 2006 the number of students studying in a foreign country increased 9 times. Since the 1980s, modern globalization has spread rapidly through the expansion of capitalism and neoliberal ideologies. The implementation of neoliberal policies has allowed for the privatization of public industry, deregulation of laws or policies that interfered with the free flow of the market, as well as cut-backs to governmental social services. These neoliberal policies were introduced to many developing countries in the form of structural adjustment programs (SAPs) that were implemented by the World Bank and the International Monetary Fund (IMF). These programs required that the country receiving monetary aid would open its markets to capitalism, privatize public industry, allow free trade, cut social services like healthcare and education and allow the free movement of giant multinational corporations. These programs allowed the World Bank and the IMF to become global financial market regulators that would promote neoliberalism and the creation of free markets for multinational corporations on a global scale. In the late 19th and early 20th century, the connectedness of the world's economies and cultures grew very quickly. This slowed down from the 1910s onward due to the World Wars and the Cold War, but picked up again in the 1980s