FACTBOX: Strait of Hormuz: economic effects of disruption

(Reuters) - A cargo ship contracted by the U.S. military fired on an Iranian vessel in Gulf waters on Friday, raising tension between Washington and Tehran in a region vital to world oil shipments.

In January, the United States said Iranian boats aggressively approached three U.S. navy battle ships, warning them they would explode in minutes. Iran has said it was a routine contact.

In late March, warning shots also fired by a U.S. Military Sealift Command ship against a small boat, this time close to the Suez Canal, killed an Egyptian civilian.

Any military action in the Strait of Hormuz in the Gulf would knock out oil exports from OPEC's biggest producers, cut off the oil supply to Japan and South Korea and knock the booming economies of Gulf states.

Here are some key facts on what passes through the international waterway and some of the direct economic consequences of any attack on merchant shipping.

-- 2.9 billion deadweight metric tons passes through the strait every year.

-- Crude oil exported through the Strait rose to 750 million metric tons in 2006.

-- 27 percent of transits carry crude on oil tankers, rising to 50 percent if petroleum products, natural gas and Liquefied Petroleum Gas transits are included.

-- Transits for dry commodities like grains, iron ore and cement account for 22 percent of transits.