Year	% of total energy use
1971	2.1170660551993157
1972	2.2549752959505533
1973	1.7809096836043679
1974	1.8839043643641773
1975	1.8163894771241822
1976	1.8725383795033084
1977	1.9367451657763173
1978	2.1303475009150854
1979	1.877988098863694
1980	1.8418489062790182
1981	1.7264186773052432
1982	1.5373660599285008
1983	1.430138802384054
1984	1.3050738096863472
1985	1.1706418759531023
1986	1.2288657818302815
1987	1.342611500857497
1988	1.2368136050939487
1989	1.1944093589771745
1990	0.9401861376799648
1991	0.8802821682382381
1992	0.8779337484197332
1993	0.8219025181882079
1994	0.7164569872432811
1995	0.6834800094537049
1996	0.7506154310421426
1997	0.6917616517122589
1998	0.7075959203306537
1999	0.6495421513458052
2000	0.5796347951154367
2001	0.6148631488320263
2002	0.602303035371949
2003	0.7049437036154877
2004	0.6688233659902779
2005	0.7930120976984649
2006	0.8087800877993077
2007	0.7891187856552141
2008	0.495245072064993
2009	0.5229416779751938
2010	0.6344171074009587
2011	0.6615711746566145
2012	0.7344441871648839
2013	0.9461394694435853
2014	0.860316001680588