Year	% of total fuel combustion
1971	17.121439280359823
1972	17.17435451116913
1973	16.51017214397496
1974	19.934558268311097
1975	17.816492450638794
1976	17.126238690219733
1977	15.952143569292126
1978	14.436172144543308
1979	14.699215344376634
1980	17.81609195402299
1981	18.83116883116883
1982	19.27599418681464
1983	20.1609812188578
1984	20.967538208917517
1985	23.07243671993468
1986	24.320327607780687
1987	28.425935262680245
1988	27.76125131945111
1989	28.835473003733043
1990	35.24000893056486
1991	35.618885580603994
1992	37.07748525869945
1993	36.868894179459815
1994	36.30213239701978
1995	35.25504666811374
1996	35.258905772531286
1997	34.96625035366396
1998	33.78915202444614
1999	34.03543235476009
2000	34.95791669664053
2001	35.067343012069266
2002	34.555707450444295
2003	31.853660213870647
2004	33.22371699053313
2005	34.057850965839435
2006	34.721907291632924
2007	34.067934953224075
2008	33.358665020107026
2009	35.51213383587912
2010	35.04221373310648
2011	34.62954510877833
2012	34.58307172541633
2013	36.98975668276478
2014	37.273253864211455