The BDI is a price index for sea transport of solids.
It was established fairly recently in 1998 by the British company Baltic Exchange.
This is an average of prices on 26 shipping routes in the world of minerals, grains, and metals in particular.
It represents a valuable indication of the health of world trade, and intensity of economic exchanges. Thus, it greatly increases during the growth period, when countries like China recently, import raw materials, mining, such as cereal. On the contrary, in times of economic crisis, when these imports decreased in 2008 as it corrects much.