Year	% of total fuel combustion
1960	3.0016644567946504
1961	3.0845539796946446
1962	3.48097378829194
1963	3.5744585845054706
1964	4.720056697377747
1965	5.5146070866444
1966	6.231846695883819
1967	6.087623286023575
1968	6.866654624779426
1969	6.872377190817083
1970	3.1555631283012437
1971	5.735245935209075
1972	5.767023301544556
1973	5.83166127604294
1974	5.521343136179086
1975	5.583821436844372
1976	5.39271197148681
1977	5.409869613518096
1978	5.448192548433131
1979	5.433789802676374
1980	5.138209520988119
1981	5.543688332824739
1982	5.06066528371609
1983	5.076763954878955
1984	5.108903485755992
1985	4.880364773226074
1986	4.979340573035623
1987	4.837180328230345
1988	4.714824814383016
1989	4.482411367424774
1990	4.164358220728123
1991	4.069129460010591
1992	3.867650005663057
1993	3.754009375771034
1994	3.89623697444548
1995	3.5616961670699094
1996	2.623640563574277
1997	3.120020542187109
1998	3.1752188947540394
1999	3.371034473171605
2000	2.367605366043163
2001	2.3882451388711456
2002	2.4094500864911326
2003	2.435306540434625
2004	2.409797059829574
2005	2.3704594865139783
2006	2.246957830088135
2007	2.0807492875596725
2008	2.0607439226593876
2009	2.043103572995887
2010	1.9503185939103658
2011	1.841716135906121
2012	1.9019855553030545
2013	1.9180012499280856
2014	1.9028414298808436