Year	% of total fuel combustion
1971	55.06547208821503
1972	55.0673281360737
1973	56.53846153846154
1974	56.01983002832862
1975	53.974484789008834
1976	51.93726937269374
1977	51.821493624772316
1978	60.841423948220076
1979	58.16993464052288
1980	65.16724336793541
1981	62.43781094527363
1982	60.768175582990395
1983	57.62463343108504
1984	59.94020926756352
1985	45.333333333333336
1986	48.717948717948715
1987	46.21212121212122
1988	43.64161849710983
1989	41.01694915254237
1990	37.96992481203007
1991	36.95652173913044
1992	34.96503496503497
1993	34.48275862068966
1994	30.418250950570343
1995	30.038022813688215
1996	29.69924812030075
1997	65.39923954372625
1998	65.37753222836096
1999	63.82189239332098
2000	63.81461675579322
2001	63.38028169014084
2002	61.69429097605893
2003	61.58088235294117
2004	62.5
2005	63.77295492487479
2006	61.96943972835314
2007	63.74999999999999
2008	62.7172195892575
2009	61.551433389544684
2010	47.031963470319624
2011	57.27272727272727
2012	65.19823788546255
2013	64.17233560090703
2014	65.68421052631578