Year	% of total fuel combustion
1971	38.84839650145772
1972	39.49375866851595
1973	38.780096308186195
1974	38.986292636276694
1975	40.12779552715655
1976	38.494623655913976
1977	39.7690257625111
1978	41.98002350176263
1979	43.06900726392251
1980	43.86271087841768
1981	43.81924198250729
1982	44.21809466746556
1983	42.527409117137914
1984	42.59314456035767
1985	44.68272620446534
1986	44.78134110787172
1987	44.39605110336818
1988	45.69627192982457
1989	45.277401894451955
1990	49.21017402945114
1991	49.35548553423089
1992	50.2419584400797
1993	49.75440624097083
1994	49.8255033557047
1995	49.10561136976231
1996	50.03523608174771
1997	48.44328325713041
1998	47.30878186968838
1999	45.36679536679537
2000	46.54300168634064
2001	46.70669256577786
2002	46.96159455517745
2003	46.91629955947136
2004	46.82064025727233
2005	45.99167822468794
2006	46.00957185357652
2007	46.70538042190093
2008	48.01181549647808
2009	49.8809266074908
2010	49.851783706429515
2011	50.85725293777692
2012	50.318922749822825
2013	51.05205800989186
2014	50.96191908795821