Year	% of total fuel combustion
1971	13.914174252275682
1972	13.96103896103896
1973	14.215384615384616
1974	15.389016018306636
1975	14.426769061985736
1976	14.64073473797947
1977	15.566556655665567
1978	16.076294277929154
1979	15.73736321000521
1980	16.28249141736145
1981	16.902071563088512
1982	17.758784425451093
1983	17.6702307259426
1984	17.374932759548148
1985	17.174515235457065
1986	18.73706004140787
1987	18.717089516515077
1988	18.861712135465662
1989	19.067357512953365
1990	17.136886102403345
1991	17.05342687533729
1992	16.5374677002584
1993	14.035964035964035
1994	12.99902629016553
1995	13.218884120171673
1996	13.322945072068562
1997	12.559055118110237
1998	13.355182302335109
1999	12.662942271880818
2000	12.428950359984842
2001	13.645704891080973
2002	14.028213166144202
2003	11.982308001608363
2004	7.927677329624477
2005	7.267645003494059
2006	6.531049250535332
2007	5.985118084762213
2008	5.65340909090909
2009	5.730963120191033
2010	5.597468970552446
2011	6.060606060606061
2012	6.136363636363637
2013	7.06958073148974
2014	6.947060054404688