Year	% of total fuel combustion
1971	43.05060584461868
1972	43.49514563106796
1973	43.2
1974	44.366645448758746
1975	46.622516556291394
1976	47.66241651487553
1977	47.929320817228046
1978	47.300000000000004
1979	48.26239750097618
1980	44.19220582671207
1981	41.42697048935376
1982	42.52721873968988
1983	43.53594569577292
1984	46.944948578342405
1985	46.107784431137716
1986	46.180641950734014
1987	44.969865554010205
1988	41.45968666411922
1989	38.6094674556213
1990	74.60431654676259
1991	62.11340206185567
1992	54.52488687782805
1993	56.85512367491165
1994	64.73651960784314
1995	63.9764996907854
1996	66.82569974554707
1997	68.42589751457501
1998	67.48197734294541
1999	72.39766081871345
2000	69.8206956146036
2001	72.93906810035843
2002	74.07123707391804
2003	70.28849756463093
2004	71.71824973319104
2005	68.93728761198642
2006	69.84693119334224
2007	71.83286412801898
2008	71.63616040240325
2009	71.90767661310889
2010	69.4816162141094
2011	69.73490427098675
2012	69.55359218786329
2013	69.48870392390012
2014	67.39079925650559