government also neutralized trade and conducted secret diplomacy with the People's Republic of China, displeasing the United States. Despite his attempts to maintain power, Luang Phibulsongkram was deposed (with Field Marshal Phin Choonhavan and Police General Phao Sriyanond) on 16 September 1957 in a coup led by Field Marshal Sarit Thanarat. The Thanarat regime (in power from 1957 to 1973) maintained the course set by the Phibulsongkram regime with US support after severing all ties with the People's Republic of China and supporting US operations in Indochina. It developed the country's infrastructure and privatized state enterprises unrelated to that infrastructure. During this period, a number of economic institutions were established, including the Bureau of Budget, the NESDC, and the Thailand Board of Investment (BOI). The National Economic and Social Development Plan was implemented in 1961. During this period, the market-oriented Import-Substituting Industrialization (ISI) led to economic expansion in the kingdom during the 1960s. According to former President Richard M. Nixon's 1967 Foreign Affairs article, Thailand entered a period of rapid growth in 1958 (with an average growth rate of seven percent a year). From the 1970s to 1984, Thailand suffered from many economic problems: decreasing US investment, budget deficits, oil-price spikes, and inflation. Domestic politics were also unstable. With the Vietnamese occupation of Cambodia on 25 December 1978, Thailand became the front-line state in the struggle against communism, surrounded by three communist countries and a socialist Burma under General Ne Win. Successive governments tried to solve the economic problems by promoting exports and tourism, still important for the Thai economy. One of the best-known measures to deal with the economic problems of that time was implemented under General Prem Tinsulanonda's government, in power from 1980 to 1988. Between 1981 and 1984, the government devalued the national currency, the Thai baht (THB), three times. On 12 May 1981, it was devalued by 1.07 percent, from THB20.775/US$ to THB21/US$. On 15 July 1981, it was again devalued, this time by 8.7 percent (from THB21/US$ to THB23/US$). The third devaluation, on 5 November 1984, was the most significant: 15 percent, from THB23/US$ to THB27/US$. The government also replaced the country's fixed exchange rate (where it was pegged to the US dollar) with a "multiple currency basket peg system" in which the US dollar bore 80 percent of the weight. Calculated from the IMF's World Economic Outlook Database, in the period 1980–1984, the Thai