Year	% of energy use
1960	45.61990106967973
1961	45.2804707663157
1962	47.59164104204914
1963	51.937052774553564
1964	55.78941553464857
1965	58.69348496835263
1966	61.103739375104205
1967	62.36489304711449
1968	66.36720814400961
1969	70.33871790906781
1970	71.99352703490027
1971	72.57189375020985
1972	74.90186231941749
1973	76.78100204891201
1974	75.75437815655522
1975	77.822518633564
1976	80.26259314119447
1977	76.37451390770522
1978	75.90881330109688
1979	72.80100456208592
1980	71.89892480278417
1981	62.157329649220486
1982	56.47789554288649
1983	56.54897825192003
1984	56.07655799387007
1985	59.83571402415521
1986	58.01600012460983
1987	63.635832385252634
1988	59.46845599470119
1989	59.21476585256554
1990	57.43277271499323
1991	61.206942270725975
1992	55.32174650594281
1993	58.49549694152961
1994	57.2256188602005
1995	54.49686471034255
1996	56.23699880847693
1997	53.383312314087526
1998	58.277991675959676
1999	52.54761584877311
2000	53.9228858518656
2001	53.781972210007254
2002	53.96340265427762
2003	56.80848691794588
2004	57.41220937238497
2005	51.45998697051524
2006	51.324112197962336
2007	56.16714915058648
2008	53.35357321438756
2009	50.279074231582186
2010	52.23543393148936
2011	51.15491807206425
2012	49.010782108590305
2013	45.30505616412006
2014	46.197275514045835
2015	45.33378502563625