Ever since steps were taken in the 1960s to liberalize Spain's economy, its trade with West European countries had steadily expanded. In 1973 EC countries accounted for 47.8 percent of Spain's exports, and they provided 37 percent of its imports. In the early 1980s, this ratio had not changed significantly in 1982 the respective figures were 48.6 and 31.8 percent. After Spain's accession to the EC, however, the balance shifted radically in 1987, some 63.8 percent of Spain's exports went to the EC, while the EC supplied Spain with 54.6 percent of its imports (see table 11, Appendix). In 1987 France was Spain's most important trading customer, taking 18.9 percent of its merchandise exports West Germany was the largest source of imports, supplying 16.1 percent of the total. The United States, which was Spain's single most important trading partner in the 1970s, accounted for just over 8 percent of both imports and exports in 1987. Increased trade with the EC caused Spain's economic interaction with most of the rest of the world to decline on a relative basis. This decline was most marked with regard to the Organization of Petroleum Exporting Countries (OPEC), which supplied Spain with 26.8 percent of its imports and received 5.3 percent of its exports in 1982, compared with 9.5 and 6.5 percent in 1987.

Data as of December 1988