Changes in the Value of World Trade per Type of Merchandise,
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.