declined to under 21% by 1988. A small increase was experienced by 1991 when mineral fuel imports increased to 23%. These shifts show the enormous impact of price changes on imports. Swings in imports of other raw materials were far less dramatic, and many declined over time as a share of total imports. Metal ores and scrap, for example, declined steadily from 15% in 1960 to less than 5% in 1988 and less than 4% in 1991, reflecting the changing structure of the economy, which moved away from basic metal manufactures to higher value-added industries. Textile materials also dropped from 17% of total imports in 1960 to just under 2% in 1988 and just over 1% in 1991, as the textile industry became less important and imports of finished textiles increased. Foodstuffs, however, were relatively steady as a share of imports, rising from just over 12% in 1960 to 15.5% in 1988. By 1991 a slight decline, 14.5%, was experienced. Manufactured goods—chemicals, machinery and equipment, and miscellaneous commodities—gained as a share of imports, but the variation among them was considerable. Manufactures were about 22% of total imports in 1960, remained at just under 23% in 1980, and then expanded to 49% by 1988. By 1991 they were just over 45%. Imports of textiles, nonferrous metals, and iron and steel products all showed significant gains, for the same reasons that the raw material imports to produce them had declined. However, chemical and machinery and equipment imports showed little increase in share until after 1985. The heavy dependency on raw materials that characterized Japan until the mid-1980s reflected both their absence in Japan and the process of import substitution industrialization, in which Japan favored domestic industries over imports. The desire to restrict manufactured imports was intensified by the knowledge that the nation needed strong manufacturing industries to generate exports to pay for needed raw material imports. Only with the appreciation of the yen after 1985, and the drop in petroleum and other raw material prices, did this sense of vulnerability ease. These trends were reflected in the rising share of manufactures in imports in the late 1980s. Balance of merchandise trade Between 1960 and 1964, Japan incurred annual trade deficits (based on a customs clearance for imports) ranging from US$400 million to US$1.6 billion. The era of chronic trade deficit ended in 1965, and by 1969, with a positive balance of almost