Year	% of total fuel combustion
1971	34.75877192982456
1972	36.035215543412264
1973	35.193386477708884
1974	37.11295246402093
1975	37.64320785597382
1976	38.07377049180328
1977	42.03528172722486
1978	47.55156269770973
1979	47.11889132020423
1980	45.67901234567901
1981	46.16997656346366
1982	47.20744680851063
1983	46.32226322263223
1984	46.10831234256926
1985	47.74413231180834
1986	50.931602356052416
1987	51.60830860534125
1988	51.755229622505404
1989	51.622668927101
1990	64.74453533592597
1991	67.90319731496201
1992	69.41415634817963
1993	69.71197945331133
1994	66.98022653100402
1995	67.21653394008344
1996	67.22452049642723
1997	58.2066276803119
1998	59.22072623419011
1999	62.337360594795534
2000	62.88219957335862
2001	65.46746613368866
2002	62.88538479642269
2003	63.38540552107853
2004	62.94759825327512
2005	62.12903225806452
2006	61.238195173137456
2007	63.79682290645224
2008	66.41252833298991
2009	69.05660377358491
2010	70.04504504504504
2011	72.42430400325136
2012	69.74128233970754
2013	68.91204880528723
2014	69.04818419178731