Year	% of total fuel combustion
1991	0.8849557522123895
1992	0.8130081300813009
1993	0.6993006993006994
1994	1.8181818181818181
1995	2.2346368715083798
1996	3.125
1997	4.060913705583757
1998	3.4653465346534658
1999	2.0202020202020203
2000	1.5789473684210527
2001	1.2345679012345678
2002	0.9433962264150944
2003	0.8928571428571428
2004	0.8547008547008548
2005	0.8032128514056224
2006	0.8
2007	0.7722007722007722
2008	0.6849315068493151
2009	0.33557046979865773
2010	0.32573289902280134
2011	0.6389776357827477
2012	0.6172839506172839
2013	0.5813953488372093
2014	0.5571030640668524