Year	% of energy use
1960	17.74362156268288
1961	18.65514963693641
1962	19.975157968001838
1963	22.19652832980051
1964	23.109247086357396
1965	24.82361355637716
1966	25.663110051187598
1967	25.780298675431588
1968	27.830029709698344
1969	30.56280846702644
1970	30.65010379036715
1971	31.970944832782518
1972	33.578583298187404
1973	36.09171828040678
1974	35.87770338184399
1975	33.84060773613326
1976	36.92717186286939
1977	36.153547123019806
1978	36.569659379177985
1979	34.485959275752954
1980	31.353898485207566
1981	28.639529225086044
1982	26.305202697037117
1983	26.71332682406242
1984	25.159013229558823
1985	24.51285881994246
1986	24.733984886421144
1987	25.093075206766883
1988	26.56489291590969
1989	27.66208294441971
1990	28.563064645199596
1991	28.995969657081474
1992	28.55334667188935
1993	29.45199994864253
1994	28.1650916151085
1995	28.199510293226755
1996	28.317063050924915
1997	28.342213181793316
1998	28.15608588007636
1999	29.61919355789591
2000	30.248330251801324
2001	29.299227293189713
2002	30.13822186518888
2003	31.79501411604878
2004	32.54355701424365
2005	33.06769583823015
2006	32.57813430319143
2007	32.7127023941103
2008	31.206152835089565
2009	28.855225710768504
2010	29.722733049252493
2011	28.43858722121402
2012	27.17667167848511
2013	25.602640230114805
2014	21.832551336758495
2015	19.521064474538143