Year	% of total energy use
1960	0.8061091873266525
1961	1.0026897227851863
1962	0.8154736857379168
1963	1.4806813793121174
1964	1.105815086661768
1965	1.409250236588663
1966	1.373220706346643
1967	1.3493500040400082
1968	1.7038788894443258
1969	1.7495392460005037
1970	1.5558481892071114
1971	1.4037204070497828
1972	1.4720677938786373
1973	1.5899848587106646
1974	1.7493403156189884
1975	1.8578654596427673
1976	2.021532171056822
1977	2.0069488043550097
1978	2.048723907943844
1979	2.197654297404374
1980	2.3553648446125215
1981	2.5635768703421165
1982	2.635384141534398
1983	2.773152050992434
1984	2.956186707673271
1985	3.0558098992103737
1986	3.146286620488807
1987	3.166500623033864
1988	3.37241829719865
1989	3.3785697477225085
1990	3.327619962613095
1991	3.3615522096955113
1992	3.433010936725362
1993	3.528768620814581
1994	3.6019792440673104
1995	3.6687754841083833
1996	3.7791160842585922
1997	3.805617430014417
1998	3.8298674452420474
1999	3.8519861365043715
2000	3.977224195247309
2001	4.047276929692367
2002	4.072372715037875
2003	4.065757336643705
2004	4.023565133833098
2005	4.028348149021344
2006	4.0534096942052855
2007	4.0320808919367055
2008	4.111713903703927
2009	4.154468060588355
2010	4.173980587738356
2011	4.255240733914509
2012	4.415230475662504
2013	4.589098239816571
2014	4.810636695006739
2015	4.800517915255666