(http://cdn.tradingeconomics.com/charts/commodity-coal.png?s=coal&v=201610170830o&d1=19160101&d2=20161231)
http://www.tradingeconomics.com/commodity/coal (http://www.tradingeconomics.com/commodity/coal)
Og nå har flere oppdaget Hockeystick'en:
https://wattsupwiththat.com/2016/10/26/the-global-price-of-coal-has-done-a-hockey-stick/
(https://wattsupwiththat.com/2016/10/26/the-global-price-of-coal-has-done-a-hockey-stick/)