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	1.3865021291859139
1972	1.4875198343006895
1973	1.5980021516653033
1974	1.8340420862157696
1975	1.9167118301710289
1976	2.091223700624574
1977	2.1003392764016944
1978	2.047722949130251
1979	2.2500553250351847
1980	2.3884638414692296
1981	2.6345574837936314
1982	2.761198585308298
1983	2.914961464826728
1984	3.119746086400229
1985	3.3062638424755435
1986	3.4242532664531438
1987	3.4786258680904725
1988	3.6707784154786203
1989	3.6717646616151445
1990	3.3816781331064565
1991	3.4731253669308075
1992	3.567989288392277
1993	3.711477695316676
1994	3.8319968321707667
1995	3.9765767115327515
1996	4.053602653775733
1997	4.141213506648521
1998	4.196558900741274
1999	4.318783058285845
2000	4.45178645757275
2001	4.56139757989791
2002	4.63519007059453
2003	4.559312195100778
2004	4.473375500143995
2005	4.452009939891076
2006	4.443240938265969
2007	4.423194261091837
2008	4.624211517991779
2009	4.735149317625993
2010	4.658651940958899
2011	4.689928573299763
2012	4.945242241954339
2013	5.142012266224288
2014	5.485748937655001
2015	4.800517915255666