Year	% of total fuel combustion
1971	47.131445170660854
1972	48.371448371448366
1973	47.60383386581469
1974	48.73577749683945
1975	48.750761730652044
1976	49.27184466019417
1977	51.66858457997699
1978	51.56081808396126
1979	52.26315789473684
1980	52.51989389920424
1981	52.647657841140536
1982	54.085045389393215
1983	54.958677685950406
1984	56.991618879576535
1985	58.94693541752366
1986	56.661676646706596
1987	56.98516729906865
1988	58.35777126099706
1989	59.780907668231606
1990	60.225540993599516
1991	60.35414165666266
1992	64.33192686357243
1993	62.44877049180327
1994	62.27001194743129
1995	60.90929351459774
1996	61.445270988310305
1997	63.22095857026808
1998	65.46339484891502
1999	65.3846153846154
2000	65.69396315885466
2001	66.4647184604419
2002	67.9831223628692
2003	67.30611575668142
2004	66.97727644270067
2005	68.75318931791121
2006	68.9032258064516
2007	68.95424836601308
2008	67.39568791686055
2009	64.3170426065163
2010	64.37235130790589
2011	68.22222222222223
2012	69.17548142120967
2013	71.56370085722732
2014	67.98577832740763