Year	% of total energy use
1960	2.7390949662729014
1961	2.8109938345510104
1962	2.7763842187707333
1963	2.7808753453657324
1964	2.788790053022188
1965	2.991221424317357
1966	3.0854687499380016
1967	3.064843749376301
1968	3.0601010631405585
1969	3.074384303067186
1970	2.9944270740888435
1971	3.1239276810327916
1972	3.3835493648879527
1973	3.5475650189940438
1974	4.202551147174631
1975	4.988240002774357
1976	4.9294485260278105
1977	5.444868051807461
1978	5.966228506099977
1979	6.048493027776272
1980	6.4905959373204585
1981	7.423825994783368
1982	8.02760854056849
1983	8.831798707121248
1984	9.686424914950232
1985	10.794953634937796
1986	11.405959576324701
1987	11.65065116851672
1988	11.94912959252941
1989	12.086604557937752
1990	12.01435313019048
1991	12.483501427174739
1992	12.404631577999583
1993	12.647450080848788
1994	12.700604282412218
1995	12.938844002186244
1996	12.947281576149903
1997	12.713717582759275
1998	12.91418059730864
1999	13.10549939162913
2000	13.034498874239112
2001	13.082850152097206
2002	13.083472294215383
2003	12.703182186817175
2004	12.934353801338759
2005	12.994529628175508
2006	13.060254198064317
2007	12.64840442890475
2008	12.87297882512461
2009	13.329450980115613
2010	13.115840504601769
2011	12.588873859508402
2012	12.115741090933874
2013	12.343006125167054
2014	12.585910227874379
2015	13.901704092159815