Year	% of total energy use
1960	27.872272025186422
1961	30.243309235409587
1962	30.78264333372564
1963	30.289980751164457
1964	31.832583385072294
1965	30.408899370262056
1966	31.23877892193361
1967	33.75934197762264
1968	34.48371372994412
1969	42.95602262176077
1970	45.65385237753994
1971	46.8714849156823
1972	49.821341906316064
1973	48.3861942216394
1974	48.06087850103441
1975	52.33503089072011
1976	54.92380835843878
1977	54.44677000525464
1978	55.55475478925702
1979	57.44932435878171
1980	60.40200078433311
1981	66.17852658521274
1982	70.19316647752474
1983	71.54236027128165
1984	69.34680916409714
1985	70.73359304493975
1986	68.9892680321013
1987	68.12658075830846
1988	69.68234285920383
1989	69.83860012771689
1990	32.05085837184028
1991	34.675259067544665
1992	36.39272453818038
1993	34.700677649338644
1994	34.97702556678339
1995	35.71393032370025
1996	32.681449545687805
1997	35.3051816842042
1998	35.969198592511596
1999	35.17771222692415
2000	33.66640159230574
2001	36.07883604476185
2002	36.290845955186136
2003	36.25981840682728
2004	37.62791392581315
2005	37.491929304608355
2006	33.1078916864554
2007	31.842374958699377
2008	35.82463253729819
2009	35.212076651240714
2010	35.02220562553276
2011	33.23223483770816
2012	35.52822395771249
2013	34.833617305932094
2014	35.433148108588426
2015	37.516934133248476