Year	% of energy use
1960	33.984951865990205
1961	36.83426680157188
1962	41.86746891477505
1963	45.88087886372014
1964	47.40246454761081
1965	50.42424932724989
1966	53.291575846324726
1967	57.51087060925942
1968	60.14089471830065
1969	61.94326753080868
1970	58.99515402694183
1971	59.36485811230787
1972	60.61175279120769
1973	62.48865323786193
1974	60.77898934102305
1975	58.39009038794492
1976	60.84061343162316
1977	59.9189861436963
1978	61.94418839600477
1979	61.993031829823614
1980	60.69848583028423
1981	57.47267940223781
1982	56.20200379784842
1983	55.0506113059349
1984	53.59573284568321
1985	52.251336595808546
1986	52.86848448412293
1987	53.67162463011081
1988	54.039009585517114
1989	53.84836848415714
1990	55.378526318653854
1991	56.676438474766776
1992	56.16277280758029
1993	56.30350022120307
1994	57.200571726840884
1995	58.138688185111455
1996	58.29796322209428
1997	59.10106952406552
1998	61.035409563474275
1999	61.18141504442216
2000	61.658482334351476
2001	62.12501543273236
2002	61.93219955886904
2003	62.36608253171086
2004	62.02502309524604
2005	62.698260328046096
2006	62.610938930877126
2007	62.333682284143926
2008	61.7639921493861
2009	60.94928227936912
2010	60.47083201672666
2011	60.056971160502705
2012	59.47963317338706
2013	58.248008670467556
2014	57.721670111154594
2015	59.83882384373537