Year	% of total fuel combustion
1971	28.570729439400985
1972	28.40204053495106
1973	28.054600395957067
1974	26.754793897057365
1975	24.907720402533318
1976	24.341651229523087
1977	25.396329287562295
1978	25.733524168889467
1979	26.091065684974314
1980	27.124699818426752
1981	27.221026297416802
1982	27.637763487989844
1983	28.157611975448564
1984	28.78237363020667
1985	28.305720090422643
1986	30.598194286028384
1987	29.333545664463728
1988	30.462646405033343
1989	30.58518304987028
1990	29.798324856398192
1991	30.179270754785826
1992	30.67136889193955
1993	30.207496499644225
1994	30.36656046453465
1995	30.116096442821974
1996	30.070614556386776
1997	31.252760886115208
1998	32.84921243850702
1999	32.59729002235504
2000	33.45413482496914
2001	33.90920258226392
2002	33.40664308005251
2003	34.36234170468597
2004	33.59204109078536
2005	33.935952438842655
2006	33.77014818044814
2007	34.03614680663753
2008	33.83140006346296
2009	35.029412189798954
2010	33.71018795285251
2011	33.13164263916657
2012	34.45053418533579
2013	34.92180519715837
2014	35.100437164517736