Year	% of total fuel combustion
2005	18.181818181818183
2006	18.666666666666664
2007	21.32701421800948
2008	19.18819188191882
2009	15.116279069767444
2010	3.571428571428571
2011	3.937007874015748
2012	4.273504273504274
2013	7.488986784140969
2014	6.756756756756756