Year	% of total fuel combustion
1971	61.33497042080588
1972	60.271149674620396
1973	59.50057706431645
1974	59.78619242681587
1975	59.097993376193244
1976	59.97094079186342
1977	59.44449251535866
1978	58.4839940288605
1979	58.96201177100054
1980	57.527699326526196
1981	56.42195395845031
1982	56.91035218783352
1983	55.96949067070095
1984	56.370302474793775
1985	56.876722175631954
1986	56.72493542380008
1987	55.07688552599464
1988	53.917269171506454
1989	51.94090555655242
1990	51.775542358501994
1991	50.65031586770717
1992	48.384237796563944
1993	48.07875283612675
1994	45.60230897766976
1995	43.24700425202937
1996	39.42931258106355
1997	38.950612277998545
1998	38.115561391989495
1999	38.99444835405426
2000	38.41653088431344
2001	38.377347832227095
2002	37.104424778761064
2003	37.366159721748616
2004	35.93084932224478
2005	35.26073075558708
2006	35.04452890124227
2007	32.19795869926418
2008	32.772644275991816
2009	32.43873978996499
2010	33.25124563312525
2011	29.57670892869122
2012	31.37656261422618
2013	28.068475452196378
2014	29.748934154429183