Source: Worldwatch Institute. United Nations, Review of Maritime Transport.

International Seaborne Trade and Exports of Goods, 1955-2005

The growth of maritime transportation is strongly correlated with the growth of international trade. From about 800 million tons loaded in 1955, maritime traffic exceeded 7.1 billion tons in 2005. Indeed, 25,000 billion tons-km of freight are on average transported annually by maritime transportation compared to 7,000 by rail and 3,000 by road. Major fluctuations in the value of exports in the 1970s and 1980s were mainly linked with economic recessions. More recently, the development of containerized maritime transportation was linked to a growing trade of value-added commodities. For every $1,000 of exports, there is one ton of freight being shipped by maritime transportation. From the late 1990s, a growing disconnect took place between the volume and value of maritime trade, mainly the outcome of the increasing sophistication of goods manufactured in Pacific Asia, rising energy (oil) prices as well as the fragmentation of production.