Year	% of total energy use
1960	0.21663987034784252
1961	0.2377603927757786
1962	0.22503747733417062
1963	0.32702229734523197
1964	0.2693909285689231
1965	0.3418797826076151
1966	0.34383261453327535
1967	0.3420781144943432
1968	0.40668964881378256
1969	0.38688906916952087
1970	0.42920050651340247
1971	0.6115023810892024
1972	0.754554410448269
1973	0.7284313613069647
1974	0.9211166628158364
1975	1.2346691076889922
1976	1.5150678701171885
1977	1.6310201037558059
1978	1.5909053269364841
1979	1.680600646587123
1980	1.7682054087016892
1981	2.2027527671366824
1982	2.2745572554603606
1983	2.283139690012474
1984	2.475996715481617
1985	2.4106321826822446
1986	2.246750334897923
1987	2.4161810403606636
1988	3.1647877187810614
1989	2.747418955390676
1990	4.497910077928572
1991	4.622358687737181
1992	4.978097459340504
1993	5.395848191057282
1994	5.510882216247058
1995	5.726457621710256
1996	6.215577046821702
1997	6.482344967593364
1998	6.508724858300303
1999	6.780917821479162
2000	7.022755548107225
2001	7.155313207411925
2002	7.256784976702729
2003	7.137214443105746
2004	7.29119292336079
2005	7.438521354650295
2006	7.381381816620036
2007	7.29394002080755
2008	7.271173248726859
2009	7.781282717198859
2010	7.739109103185188
2011	7.451111545413096
2012	7.5184857325238035
2013	7.602567974014526
2014	8.173807104104357
2015	4.329765885142349