Year	% of total energy use
1960	4.486547313204029
1961	4.124450709042265
1962	3.6361234975897334
1963	4.053779554163139
1964	3.1152281288403993
1965	4.096395017155143
1966	4.592995105353784
1967	4.100688947161999
1968	4.383611672880581
1969	4.498414764749059
1970	4.1765127185072295
1971	4.211632358698758
1972	4.809212628827364
1973	4.436840789994579
1974	4.999917609815377
1975	6.045883215143643
1976	4.730141118063318
1977	6.537142829764425
1978	7.527915102257989
1979	8.426107538700322
1980	11.472644539351878
1981	18.00517180992916
1982	18.891333230338372
1983	23.279906555037634
1984	28.612204502563323
1985	31.339126070734004
1986	34.67537016720791
1987	35.5592360223943
1988	37.19756410036399
1989	37.92262507848051
1990	38.27005326203302
1991	38.19109367264156
1992	39.97633199955823
1993	42.47347777378291
1994	43.58894415913712
1995	43.60603893854535
1996	43.205286726495906
1997	44.33669126977216
1998	42.29555090920304
1999	43.27837523612922
2000	44.90990947235642
2001	44.24395791656023
2002	45.36568894660182
2003	44.99673696072296
2004	45.08325449537271
2005	44.93595551600136
2006	45.68903666226276
2007	45.282408345301796
2008	45.28581845477197
2009	44.2373741287801
2010	44.97926435599345
2011	47.72007847594655
2012	46.45041143204749
2013	46.446122693563076
2014	49.590417180807876
2015	49.06154063481834