Year	% of energy use
1971	10.596851693524151
1972	9.467766242130747
1973	9.827834289989282
1974	8.291131129800847
1975	6.026978718817738
1976	5.1053165204236635
1977	8.65091195822648
1978	7.26067200357691
1979	7.338615075049687
1980	9.428113822181077
1981	6.559890013893222
1982	7.52924736213353
1983	7.886470169961575
1984	6.994617768696812
1985	6.9518160548648815
1986	7.567355910111479
1987	7.345714108882702
1988	7.331499557784205
1989	7.141184211993791
1990	5.299956264996966
1991	4.939770830056921
1992	5.667589127470453
1993	6.3484336220287
1994	5.63063282775269
1995	5.99357002621447
1996	6.166299620373436
1997	6.584568026433285
1998	-1.7282875428260291
1999	-2.5480420378326287
2000	-1.1908524529962825
2001	-0.02465991250964998
2002	-1.5426646713440229
2003	4.11181513675249
2004	-8.160794299480285
2005	-18.700681077496053
2006	-22.654326784658057
2007	-21.28973903765908
2008	-23.28186217972993
2009	-22.1747844236349
2010	-22.55164379017509
2011	-24.981523840832768
2012	-50.85034982023172
2013	-53.47892405003075
2014	-54.60162753943163