Year	% of energy use
1960	86.6152011506662
1961	87.39548763574976
1962	86.98258161560679
1963	84.12544410646949
1964	85.90700356878033
1965	84.3381567266525
1966	83.78173211319982
1967	84.84018176584829
1968	84.78480942478997
1969	83.67454769268477
1970	78.00220165754999
1971	76.00785536571398
1972	78.51079070002612
1973	80.23584309401863
1974	78.27279812246185
1975	75.07589027115291
1976	72.86273804052688
1977	73.56568735027527
1978	75.77994795920992
1979	75.33235820053063
1980	75.33132158799954
1981	69.84218924863046
1982	63.37900353507162
1983	62.227127484718125
1984	60.721804781594855
1985	60.50384053633901
1986	56.69349848690016
1987	55.07391430516647
1988	56.798977147069664
1989	58.056337690703295
1990	57.098555276080155
1991	58.20248672057866
1992	59.566173548188814
1993	58.950349063352846
1994	59.29578870778578
1995	58.998978939592874
1996	61.03129300125213
1997	60.71296902227965
1998	61.62497215532409
1999	62.93212059242613
2000	63.13240619694037
2001	64.41668939572975
2002	63.88291338327723
2003	66.00878637952624
2004	65.31408152589401
2005	65.89463961980701
2006	66.68933019352501
2007	66.34261878155647
2008	67.58740178088219
2009	65.77147976923551
2010	65.82322603507347
2011	64.02047022132803
2012	60.751623727612724
2013	60.119869276216775
2014	61.97067022304862
2015	64.17554663878474