Year	% of total energy use
1971	1.0844809078679067
1972	1.1190141266475642
1973	1.2144383479202208
1974	1.2918711668280431
1975	1.3373773901023458
1976	1.384875339490343
1977	1.3531890700527012
1978	1.115849493137054
1979	1.4131985941809586
1980	1.458066109191151
1981	1.481267378722785
1982	1.4285195338697434
1983	0.9937846227979997
1984	0.9290818029384885
1985	1.23168384240069
1986	1.4116514702131226
1987	1.3478601522551363
1988	1.4411697750551586
1989	1.504345557321254
1990	1.1439334910685777
1991	1.2134488943781896
1992	1.200184272591239
1993	1.2093654267333576
1994	1.1392368940857474
1995	1.24021132680937
1996	1.2253337308960646
1997	1.1670442640143586
1998	0.9159701911115287
1999	1.0086325826062132
2000	1.0392840427705876
2001	0.983827779943254
2002	0.9703375846174538
2003	0.8626638532887647
2004	0.931576548449471
2005	0.92415755811999
2006	0.8377385492275168
2007	0.7997195977527028
2008	0.8941475443290854
2009	0.8570324487361124
2010	0.8386976985275697
2011	0.8531970118251289
2012	0.8550891302444571
2013	0.8148064015409566
2014	0.83419708268076