Figure 12 gives the ratio of annual custom duties to the value of imports in 1927-84. The big dip in the latter half of the 1940s and the 1950s is actually an indication of other types of trade barriers, and the upward trend until the mid-1960s reflects the tariffication of NTBs. From the beginning of the 1960s in particular, import substitution in specific industries was clearly the objective of the escalation of tariffs. Low tariff rates were set for primary commodities, raw materials, well-established export industries, and products that did not have much hope of gaining international competitiveness. On the other hand, high tariffs were imposed on the products of newly established industries that were striving to gain international competitiveness. It is important to note that trade protection was provided only temporarily; by 1974, the ratio dropped to 2 per cent, indicating that major trade barriers had been removed, particularly for manufactured goods.