Year	% of energy use
1960	39.30912722039289
1961	43.14416242412137
1962	48.94045199168765
1963	52.755791655675075
1964	53.11793986092347
1965	58.107180876027975
1966	62.420205053127596
1967	66.2743571105316
1968	73.16633061961767
1969	77.91151067752277
1970	82.16570813229457
1971	82.741679856434
1972	84.88312292602888
1973	85.84725543791252
1974	86.35342362604169
1975	81.17921938792581
1976	80.87422464531969
1977	79.92207669236568
1978	82.5751724268627
1979	84.45640829587097
1980	82.69565813134886
1981	81.22070230459755
1982	78.13933957640636
1983	73.26181791851478
1984	71.64506237945928
1985	68.35948314508563
1986	67.85291479341767
1987	68.96125442801807
1988	71.55709630127886
1989	72.82017883855026
1990	72.66476602762059
1991	74.09473376171447
1992	74.86704820885261
1993	75.52073485957904
1994	77.8473794211192
1995	77.64908961267052
1996	78.02540972763
1997	76.1671693515778
1998	77.0716496811765
1999	75.77244366752191
2000	76.36884079027622
2001	77.00948113862557
2002	75.76874717196135
2003	76.3854081453545
2004	76.4127189389874
2005	76.1110978461456
2006	76.13442796378487
2007	74.38493063795727
2008	75.64854637688637
2009	73.43279043147439
2010	74.2611828033881
2011	71.38626298760387
2012	73.70403182295519
2013	73.19206873773541
2014	76.25886030281166
2015	80.09179196696829