Year	% of energy use
1971	86.22060090448042
1972	89.07287751107617
1973	91.39593235076498
1974	90.23797045942044
1975	90.54347076250725
1976	89.53742115904377
1977	90.15284852929229
1978	89.75048202336396
1979	91.31039848342894
1980	90.17407864020018
1981	90.34111952318202
1982	89.20324713057991
1983	88.25286562691569
1984	86.41829649002915
1985	85.37220563078083
1986	85.42424747407877
1987	85.7683862086137
1988	85.81809023969579
1989	86.54202138502389
1990	82.5966028435447
1991	82.63879671293492
1992	83.5353462225952
1993	83.98328926794984
1994	83.86521958506093
1995	84.90326811673407
1996	85.25523086446348
1997	84.87780924931204
1998	86.69322266117868
1999	86.64970852618133
2000	84.55707037383972
2001	86.919410960444
2002	88.97380059566528
2003	89.34116422538804
2004	89.03314404167574
2005	88.91521342396896
2006	90.11589564729192
2007	90.32654003495826
2008	85.97678655875573
2009	82.31683794518756
2010	82.65261778479541
2011	82.49309604119271
2012	81.95419982935874
2013	82.5422588605831
2014	82.04251867744831