Year	% of total fuel combustion
1960	18.020388030253205
1961	18.597063621533444
1962	18.568433662773284
1963	17.90073230268511
1964	18.205944798301488
1965	19.287268770402612
1966	20.113390928725703
1967	20.43409211222869
1968	19.71830985915493
1969	20.58207217694994
1970	18.919500645716745
1971	19.629629629629626
1972	20.694444444444443
1973	20.72490706319703
1974	20.129107981220656
1975	20.998383185125306
1976	19.59584723767149
1977	21.47310989867498
1978	21.919850885368128
1979	22.128801431127012
1980	21.23665807876334
1981	21.066925315227934
1982	21.659634317862164
1983	22.575420125531483
1984	21.369701726844585
1985	21.12462006079027
1986	22.293240364129378
1987	22.31767850324551
1988	24.77647526326247
1989	25.72449384676459
1990	24.218194740582803
1991	24.89660876757651
1992	27.109192300773522
1993	27.27598566308244
1994	27.178939879046602
1995	26.011075683839568
1996	27.041541620597066
1997	25.899856023036318
1998	28.987802946301283
1999	28.96405919661733
2000	29.982220785518027
2001	30.253623188405797
2002	32.46484085862325
2003	32.26736206423278
2004	32.233639805300164
2005	32.93091884641181
2006	32.41513633834168
2007	33.88025331030512
2008	32.184403274450666
2009	33.91959798994975
2010	32.34309014125528
2011	32.374962563641816
2012	33.78716744913928
2013	35.46629300949712
2014	36.62388943731491