Year	% of total energy use
1960	3.501110376271565
1961	3.5294307924083315
1962	3.387302441910648
1963	3.526671449937197
1964	3.473946315138936
1965	3.905755442553254
1966	4.210265746239213
1967	4.192053967131951
1968	4.148612783428512
1969	3.9909947233553114
1970	3.6194671439094077
1971	3.3965813463414567
1972	3.6606213240170327
1973	3.6207300016900574
1974	4.045243001612359
1975	4.736270741380376
1976	4.595316888555092
1977	5.430242686757357
1978	5.565909274100456
1979	5.826758818149866
1980	6.415647763258326
1981	8.076276506565671
1982	8.713947519682405
1983	9.794459088860009
1984	11.461391002565504
1985	12.70613993735065
1986	13.232064025059678
1987	13.524724790596203
1988	14.422121563298743
1989	14.647472619929694
1990	10.085759605457511
1991	10.385591792069583
1992	11.076081064740583
1993	11.809489905066464
1994	12.21517530274118
1995	12.37305736731104
1996	12.808137991561745
1997	13.182581463965976
1998	13.171186963164331
1999	13.438346371328963
2000	13.52428767189547
2001	13.768522548663851
2002	13.790737255044842
2003	13.571180485740179
2004	13.709802834811594
2005	13.60182793504272
2006	13.501828936843504
2007	13.246211896741919
2008	13.291095050474663
2009	13.81838691309022
2010	13.739921734309924
2011	13.790750300959283
2012	13.868698661444975
2013	14.227979795315456
2014	15.09760806641937
2015	18.62998085929436