Source: WTO.
Changes in the Value of World Trade per Type of Merchandise, 1950-2011
Specific segments of international trade are subject to much volatility, particularly fuel and mining trade (e.g. petroleum), which began to diverge from other trades (agriculture and manufactures) in the 1970s. Commodity chains and the trade patterns they represent are thus subject to some level of uncertainty in assessing growth potential and the necessary level of investment in transport infrastructure, let it be for modes or terminals.