Year	% of energy use
1960	30.244338738165595
1961	32.70322953712536
1962	37.42173900395393
1963	40.96300053711615
1964	42.047720788167744
1965	44.48022891221377
1966	47.050490857673935
1967	50.67829316729572
1968	53.12027396630287
1969	55.023471094475674
1970	53.55527903199272
1971	49.89305098114205
1972	50.98398653323494
1973	52.82198313712908
1974	51.034641904786376
1975	48.610520230978
1976	50.96518170296453
1977	50.08082059526677
1978	51.60010480029588
1979	52.124732008167484
1980	51.590754417797555
1981	49.54403844114717
1982	47.1925901859888
1983	45.89048110335228
1984	44.61565796385466
1985	44.13893517585908
1986	44.56994213404284
1987	45.335119531958384
1988	45.56599465008759
1989	46.110201943886445
1990	48.35630680806187
1991	49.241473459007985
1992	48.704790645195736
1993	48.909033783704274
1994	49.488633181052634
1995	50.4958387060091
1996	50.958574629187794
1997	51.13718510783556
1998	53.49003598047779
1999	53.63876892966836
2000	53.96564982065305
2001	54.461077753416326
2002	54.302587756257005
2003	55.00105388071148
2004	54.519321883260645
2005	55.19804935457926
2006	55.56129251314692
2007	55.71405338957495
2008	55.27712423797745
2009	54.46620551063535
2010	54.58650340336064
2011	53.97238119038806
2012	53.00801173409479
2013	52.35599125705296
2014	51.875363516551054
2015	54.7035045160894