Year	% of energy use
1971	27.13549390270239
1972	26.87795699341041
1973	28.215382863402322
1974	27.252582666002787
1975	27.78357169945609
1976	29.10745720813514
1977	30.96520723462996
1978	30.384451703434472
1979	30.690387555156008
1980	29.718118451624214
1981	28.309837873530487
1982	32.053242988820365
1983	29.625227782902947
1984	30.415266584135487
1985	26.648927265958594
1986	28.030911759578238
1987	27.877927883609388
1988	29.503122157641737
1989	30.940900378964763
1990	28.809388231091678
1991	29.10312367600688
1992	32.2964500388262
1993	33.39570919715697
1994	37.13295669911202
1995	41.18169057375598
1996	40.12926676064594
1997	38.540284041909864
1998	42.98257299892914
1999	49.48675474603501
2000	49.06578677256779
2001	53.63375639293917
2002	54.616161384411896
2003	55.513808574605115
2004	57.30567073021866
2005	54.976855090359436
2006	50.46791010336765
2007	54.8057672661566
2008	55.32465265311405
2009	50.71365250116619
2010	51.1836182553413
2011	52.223267189475266
2012	51.61074850967198
2013	51.536591238843144
2014	52.99643628878778