In the 1960s and 1970s, the country's abundant natural resources, an enterprising and competitive private sector, and cautious and pragmatic economic management resulted in the emergence of one of the fastest growing and most successful economies among the developing countries. Between 1960 and 1970, the country's average annual growth rate of gross domestic product ( GDP) was 8.4 percent, compared with 5.8 percent for all middle-income, oil-importing countries. Between 1970 and 1980, the GDP rate of growth was 7.2 percent, compared with 5.6 percent for the middle-income oil-importing countries. The world slowdown by the late 1970s was mainly caused by the rise in oil prices. The Thai GDP in 1982 was US$36.7 billion. It rose to US$42 billion in 1985. The projected rate of growth for GDP during the early 1980s was around 4.3 percent as a result of falling demand and prices for Thai exports despite a drop in oil price. It was apparent that in the 1980s Thailand had lost its momentum; its Fifth Economic Development Plan targets had not been met because of serious macroeconomic imbalances, such as decreasing savings and investment rates, increasing budget deficits, and increasing debt and debt- servicing obligations. Whether Thailand could regain its former momentum depended on the success of its Sixth Economic Development Plan (1987-91).
Between 1970 and 1980, investment represented on the average 25.2 percent of GDP, compared with 24.7 percent by the mid-1980s. This proportion was one of the lowest investment rates in Southeast Asia. The national savings rate had fallen even more, from an average of 22 percent during the 1970s to around 17.8 percent by the mid-1980s. Hence, the average current-account deficit of 7 percent of GDP during the early 1980s had been caused by a declining savings rate rather than by an increase in investment rate. This imbalance was more serious than one caused by rising investment because rising investment could pay for itself with increased output and, possibly, increased savings so that debt could be repaid. With falling savings, foreign borrowing was used not to raise investment but merely to fill the investment-savings gap, which was mirrored in the external debt ratio of 39 percent of GDP and 146 percent of exports by the mid1980s . The total debt service ratio went up from 17.3 percent in 1980 to more than 25 percent by the mid-1980s. The increase was an important factor in the decision of the government to sharply reduce authorization for new commitments of public debt.