Year	% of total fuel combustion
1971	35.24590163934426
1972	37.6
1973	36.95652173913044
1974	34.01360544217687
1975	33.54037267080746
1976	35.714285714285715
1977	35.16483516483516
1978	35.79545454545455
1979	35.38461538461538
1980	35.29411764705882
1981	34
1982	34.715025906735754
1983	38.7434554973822
1984	37.745098039215684
1985	35.37735849056604
1986	34.80392156862745
1987	31.400966183574887
1988	27.41116751269036
1989	33.17307692307692
1990	34.27230046948357
1991	35.21126760563381
1992	34.05172413793104
1993	33.6283185840708
1994	31.759656652360512
1995	31.451612903225808
1996	32.69230769230769
1997	32.05574912891986
1998	31.974921630094045
1999	30.98591549295775
2000	33.23863636363636
2001	30.54830287206266
2002	32.6530612244898
2003	37.00787401574803
2004	34.234234234234236
2005	31.601731601731604
2006	34.909909909909906
2007	40.76305220883533
2008	41.7624521072797
2009	36.312849162011176
2010	37.72893772893773
2011	37.9965457685665
2012	37.03703703703704
2013	38.833333333333336
2014	38.853503184713375