By John S. McClenahen July's 1.6% drop in the import price index, the biggest monthly decline in such U.S. Labor Dept. data since December 1992, should all but erase any concerns about inflation arising from the goods that U.S. businesses and consumers continue to buy abroad. A major factor in July's price-index drop was a stunning 6.1% fall in petroleum prices. Indeed, during the last 12 months, prices of petroleum imports have declined 16.3%, says the Labor Dept.'s Bureau of Labor Statistics. On the other side of the trade ledger, the price index for U.S. exports fell 0.4% in July, as declines in prices for industrial materials and other non-agricultural goods more than offset price gains for soybeans, corn, and other agricultural exports. Led by lower prices for computers, computer peripherals, and semiconductors, the export price index for U.S. capital goods fell 0.3% in July, its largest decrease since December 1999.