Year	% of total fuel combustion
1971	32.678663933872386
1972	33.583233941046174
1973	33.55892874407812
1974	34.20810313075506
1975	35.508368086540045
1976	35.406331509231315
1977	34.83356392935623
1978	35.019348128661235
1979	34.996474160634364
1980	34.53958757461188
1981	35.780309396222776
1982	35.46446443709152
1983	34.30914651098137
1984	34.04124050563492
1985	33.74342382512472
1986	33.86554731735384
1987	33.316921056950605
1988	33.170629232366174
1989	33.22242892577753
1990	34.711173441013614
1991	35.2060408911019
1992	35.17512772126846
1993	35.76889923764959
1994	35.430358278566885
1995	35.77977857947673
1996	35.55875402374863
1997	34.73010715394023
1998	34.567684516338545
1999	34.59666911888533
2000	33.754211618963346
2001	33.879674906989166
2002	33.89978324188851
2003	33.82532700255282
2004	34.32338796431058
2005	34.48695665490073
2006	34.61808564683382
2007	35.104953699021976
2008	34.84120142073864
2009	35.12585973615966
2010	35.150056531541956
2011	35.84123413144786
2012	36.35577410148383
2013	35.95562680503206
2014	36.3160081657724