Year	% of total energy use
1960	1.0921226349394562
1961	1.2166931453143204
1962	1.240643143359296
1963	1.5781656011322247
1964	1.572711939937932
1965	1.8083526705313424
1966	1.470216608551343
1967	1.5044074397264022
1968	1.4474593018368893
1969	1.5479451562957165
1970	1.5040371234884669
1971	1.9296491018688011
1972	1.8718114980777258
1973	1.7199713915896833
1974	1.9307696510940835
1975	2.097094876489122
1976	2.102868036236986
1977	1.7151970109215204
1978	1.8100672128991575
1979	1.9642094986359877
1980	1.6270456743828858
1981	1.7625245558716585
1982	1.6405393358542721
1983	1.5433055533819957
1984	1.49723637875791
1985	1.6893833541956795
1986	1.796414987492996
1987	1.6113058527785977
1988	1.6861316536777038
1989	1.5750176821299822
1990	1.2738733078639703
1991	1.4389571078222307
1992	1.363646593565473
1993	1.4002955294462276
1994	1.3907027475527625
1995	1.3275610723862787
1996	1.2290255979902363
1997	1.2838744934949675
1998	1.1702282070407752
1999	1.1975118727026575
2000	1.1830778143535252
2001	1.2291578270378634
2002	1.213031749671404
2003	1.2247980514186094
2004	1.1797493320610009
2005	1.1297857509415115
2006	1.174375273992799
2007	1.1690255962543923
2008	1.0482222966642716
2009	1.120280273644026
2010	1.3402455020776685
2011	1.673824991113072
2012	1.7207410460358883
2013	2.138830763347635
2014	2.373422496843382
2015	2.154394200008845