Year	% of total fuel combustion
1971	30.08849557522124
1972	32.93172690763051
1973	36.12167300380228
1974	37.63837638376384
1975	38.205980066445186
1976	33.793103448275865
1977	35.92814371257485
1978	33.86666666666667
1979	31.828978622327792
1980	32.066508313539195
1981	34.710743801652896
1982	36.67711598746081
1983	40.72727272727273
1984	39.48220064724919
1985	39.93710691823899
1986	52.58620689655172
1987	52.20588235294117
1988	53.448275862068975
1989	52.30263157894737
1990	53.271028037383175
1991	52.19941348973607
1992	44.31279620853081
1993	44.27645788336933
1994	44.105691056910565
1995	46.245733788395896
1996	47.20279720279721
1997	47.833333333333336
1998	44.633507853403145
1999	47.66977363515313
2000	44.75524475524475
2001	45.49499443826473
2002	45.38860103626943
2003	50.72614107883817
2004	46.2890625
2005	48.30508474576271
2006	49.20037629350894
2007	48.12554489973844
2008	48.585365853658544
2009	50.044523597506675
2010	54.94186046511628
2011	52.48091603053435
2012	52.40793201133145
2013	48.690671031096564
2014	39.96282527881041