Year	% of total energy
1971	6.545524410467986
1972	5.869825275588196
1973	4.8040760744832225
1974	5.400557688906388
1975	5.498038021135645
1976	5.636267639722974
1977	4.908883947319921
1978	4.63771719091854
1979	3.9621570250150504
1980	3.9896619634998274
1981	3.7956613094989238
1982	4.150268504630323
1983	4.035421475519749
1984	4.254301294086563
1985	4.133534019575418
1986	4.268706037967334
1987	4.596527698800396
1988	4.228146727521298
1989	4.634378938047068
1990	1.8253599744913922
1991	1.834255035702684
1992	1.771423562911456
1993	1.893318575731877
1994	1.9317428564858008
1995	1.9898314982513565
1996	1.8098997242922867
1997	1.934364937003479
1998	1.664703320549813
1999	1.5361458852018157
2000	2.284233978941859
2001	2.0303357466036474
2002	2.1131637386468918
2003	1.9558232466001617
2004	1.947163314230749
2005	1.7515863113538794
2006	1.5981124923499892
2007	1.4899988646685303
2008	1.5101853078094254
2009	1.4857587498840086
2010	1.256641114311195
2011	1.3253441193942612
2012	1.587335902884951
2013	1.5938874714370852
2014	1.6136984510853116