Year	% of total energy use
1971	0.81917504627704
1972	1.058803514720279
1973	1.341085272925327
1974	0.8241100885520192
1975	0.5109555292260658
1976	0.5309653891637922
1977	0.32803482551791613
1978	0.2476033435894861
1979	0.22750476831849284
1980	0.197246491806667
1981	0.2583752795043292
1982	0.2595926033311717
1983	0.11784857140824552
1984	0.22869889964835605
1985	0.31309459710627013
1986	0.10726614906841594
1987	0.21681064040378492
1988	0.07531741423036831
1989	0.09380701402901366
1990	0.040035725775084297
1991	0.07818842622070886
1992	0.05341690011838379
1993	0.08860123454618705
1994	0.04324464901794191
1995	0.05037000666102321
1996	0.03600259923835023
1997	0.018955530535947524
1998	0.051813591072404463
1999	0.04645801874344566
2000	0.01258641671475956
2001	0.016202007985033715
2002	0.012708382655506981
2003	0.056891222923000494
2004	0.052381570951203146
2005	0.11571674468492277
2006	0.040560302891029604
2007	0.03970359628723065
2008	0.04860882185117818
2009	0.0468007217940375
2010	0.02731894846002887
2011	0.07228772214116785
2012	0.08267708775379111
2013	0.04298316258307706
2014	0.030106036126163478