IN 1977, the merchandise trade accounts of the United States recorded the largest deficit to date-$31.4 billion. Viewed in historical perspective, any U.S. trade deficit is an unusual occurrence: until 1971, the U.S. trade balance had been in surplus throughout the twentieth century. In 1977, the United States had a deficit of 1.7 percent of the gross national product,o r 11.5 percent of the combined value of merchandise exports plus imports. (By comparison, Italy's trade deficit in 1974 was 10.3 percent of trade value; the deficit of the United Kingdom was 4.7 percent in 1967 and 12.1 percent in 1974.) The U.S. invisibles account showed a substantial surplus, however, so that the estimated current-account deficit in 1977 of $19.3 billion was 7.1 percent of the value of merchandise trade.