Year	% of total fuel combustion
1971	15.548539857932123
1972	15.961138098542676
1973	20.8997722095672
1974	19.455445544554458
1975	18.525099955575296
1976	15.135135135135137
1977	15.974440894568689
1978	21.29471890971039
1979	31.553925563705516
1980	39.70425510512021
1981	37.92828685258964
1982	35.710297519342745
1983	30.78691685826596
1984	12.34009892546478
1985	10.97809475292919
1986	10.940401823400306
1987	9.710378735499733
1988	10.227683411637154
1989	10.87602347655967
1990	18.639131585914743
1991	17.905512812360907
1992	18.889930840464185
1993	17.36821726865424
1994	19.51598694097528
1995	20.874647740319382
1996	22.62519042704801
1997	20.371450797355113
1998	22.264613707589593
1999	23.143602671266194
2000	22.543377243466768
2001	21.93586299529886
2002	23.513280576666933
2003	23.38228114320051
2004	23.33002411005531
2005	22.73795140287287
2006	23.14180118141328
2007	23.989792854998495
2008	24.486489455184532
2009	23.990511333684765
2010	26.661894535910278
2011	25.51086156111929
2012	25.031294513748005
2013	24.431046195652172
2014	24.104305256716476