Year	% of energy use
1971	-45.6442670155033
1972	-54.482667949879996
1973	-60.84768319938557
1974	-67.31916369935044
1975	-51.12304183131642
1976	-58.928865569899855
1977	-58.8077409485305
1978	-50.94938284665056
1979	-64.25630730755313
1980	-57.15400710310094
1981	-39.922765928253035
1982	-35.27013962527742
1983	-36.13191315516684
1984	-42.70197494035862
1985	-47.53395659194517
1986	-45.99802652653227
1987	-41.70996309132011
1988	-44.65569038189308
1989	-50.88159037353213
1990	-52.63681146823222
1991	-51.91316469427429
1992	-55.30082606249239
1993	-54.220408231603976
1994	-56.0537751828377
1995	-55.6676079526732
1996	-57.66143953073861
1997	-61.60478839226252
1998	-60.70871019874642
1999	-57.085784663467095
2000	-61.156440239032335
2001	-59.05236006322011
2002	-55.417231846751356
2003	-58.41938136357473
2004	-58.446942954958445
2005	-60.945792249293056
2006	-62.200928978354696
2007	-61.36835078836857
2008	-57.50114513318715
2009	-55.21599798734084
2010	-58.18464697702541
2011	-54.577362141038826
2012	-51.5709810455869
2013	-48.12737029537662
2014	-48.803135597339235