Year	% of energy use
1971	8.370578766987597
1972	7.81769798690277
1973	7.349560127353051
1974	6.113422838523366
1975	6.306605851164545
1976	3.8096433101108103
1977	1.114129136466955
1978	0.8703152787005578
1979	-4.265040727116317
1980	-6.223554021043086
1981	-5.9913768811221475
1982	-6.0560398823356465
1983	-8.901657208550722
1984	-12.439199210067697
1985	-16.847876753152715
1986	-17.203229550104645
1987	-16.693278372205825
1988	-18.578781784439716
1989	-19.75433572748071
1990	-21.064620393017243
1991	-20.010177978710583
1992	-24.052311693038547
1993	-22.801165912310957
1994	-24.114369201465365
1995	-24.882662525092908
1996	-24.700334650081277
1997	-27.250867903962664
1998	-28.9027419345229
1999	-28.44349004445928
2000	-31.391070072852905
2001	-29.13632284347448
2002	-32.91088405070469
2003	-32.41999432255016
2004	-31.161816068631765
2005	-35.93942330253961
2006	-38.80578932422207
2007	-41.694275482213
2008	-40.02563909248594
2009	-38.31427095345399
2010	-38.2841587171351
2011	-34.62272531002425
2012	-32.244991553423205
2013	-32.03500673068137
2014	-31.65542611837299