Year	% of total fuel combustion
1971	27.292576419213972
1972	27.710843373493972
1973	25.195618153364634
1974	27.5808936825886
1975	25.91943957968476
1976	29.142857142857142
1977	26.89804772234273
1978	25.344827586206897
1979	24.126984126984127
1980	27.819548872180448
1981	31.753554502369663
1982	33.119658119658126
1983	36.801541425818876
1984	36.51376146788991
1985	34.64447806354009
1986	29.320113314447593
1987	29.183955739972333
1988	27.23948811700183
1989	33.756805807622506
1990	33.756805807622506
1991	33.52517985611511
1992	46.81159420289855
1993	37.32673267326733
1994	31.949458483754512
1995	32.6817826426896
1996	32.53193087903832
1997	27.38017071569271
1998	29.993275050437123
1999	27.15654952076677
2000	28.591851322373124
2001	24.686468646864686
2002	24.834437086092716
2003	26.578073089700993
2004	26.398946675444368
2005	28.00829875518672
2006	28.550512445095166
2007	25.562031640299747
2008	28.218135700697527
2009	26.569797612869746
2010	27.802197802197803
2011	27.405405405405407
2012	25.476190476190474
2013	24.563953488372096
2014	24.407688869021012