Year	% of total energy use
1971	0.40797544311165157
1972	0.36233720747032744
1973	0.44516338374876163
1974	0.46192810357792685
1975	0.5337083262912801
1976	0.6159240468251279
1977	0.5809727597962192
1978	0.4465618331646565
1979	0.6095404282197896
1980	0.48985716616632613
1981	0.402582198337759
1982	0.3968297060988269
1983	0.3103777814406519
1984	0.41539324459874544
1985	0.46560347456851253
1986	0.5417248663426903
1987	0.47361049893175017
1988	0.5613563218731499
1989	0.5602768526773544
1990	0.3320821994318374
1991	0.42890872221770626
1992	0.4223085999547493
1993	0.4492640203811687
1994	0.4120542927061578
1995	0.38194618976849837
1996	0.3431168448915878
1997	0.33227271994746316
1998	0.35020046458495685
1999	0.33999962623785623
2000	0.3301301457111111
2001	0.326005623514003
2002	0.4504228765961054
2003	0.41134967066232403
2004	0.45150415605855293
2005	0.4628552782465007
2006	0.33159319927645803
2007	0.4128072101749309
2008	0.37714018218348067
2009	0.3166638604106872
2010	0.3616527853366242
2011	0.34606368954930683
2012	0.3193758884378277
2013	0.2779557715938482
2014	0.27446399565924695