Total world production is about 18 million metric tons per year.[5] Copper demand is increasing by more than 575,000 tons annually and accelerating.[2] Based on 2006 figures for per capita consumption, Tom Graedel and colleagues at Yale University calculate that by 2100 global demand for copper will outstrip the amount extractable from the ground.[6] China accounted for more than 22% of world copper demand in 2008,[7] and is nearly 40% in 2014.