Year	% of total energy use
1971	0.42834786229512767
1972	0.4011787190550095
1973	0.5360571513441516
1974	0.6800702449300664
1975	0.6510900577139129
1976	0.5237330381159939
1977	0.6244629472403475
1978	0.6854522089926763
1979	0.8380316341078646
1980	0.610295543896335
1981	0.545483111807505
1982	0.5177260468676521
1983	0.42941595851176084
1984	0.4128556285734815
1985	0.35638308532236335
1986	0.3241856234105245
1987	1.415114281237129
1988	1.1735989571974919
1989	1.0651822967083389
1990	1.0598017668784356
1991	0.45711671264463916
1992	0.24205009016969567
1993	0.15979741209295434
1994	0.13208424686348766
1995	0.1403876224282001
1996	0.13882769101980147
1997	0.12003603359689752
1998	0.16836533900246858
1999	0.21792364934335853
2000	0.18500242901014208
2001	0.17052260360132512
2002	0.15001977235077218
2003	0.1381875814149971
2004	0.15912257243096792
2005	1.4463107482111917
2006	1.67500646184807
2007	1.276652918754596
2008	0.6455291972960514
2009	0.556619030131666
2010	0.7863836337903435
2011	0.512925064648215
2012	0.6277352486194013
2013	0.6390430327287183
2014	0.33070064137595706