Year	% of energy use
1971	-74.31734838054966
1972	-61.669031290892356
1973	-59.40092550629585
1974	-46.00990429997605
1975	-31.411750394229944
1976	-27.288128943972204
1977	-26.13021908508246
1978	-24.85827255920386
1979	-29.513386257959183
1980	-30.811671227573743
1981	-36.144041577973645
1982	-39.09433602783505
1983	-40.476981703464055
1984	-41.43810992899982
1985	-38.43465673214187
1986	-36.37346431004149
1987	-34.769652183451605
1988	-35.753697883559276
1989	-34.859143431048324
1990	-38.79232608377044
1991	-40.15198885166703
1992	-37.43099042748544
1993	-39.800473939167986
1994	-37.09245406354349
1995	-41.69750981265937
1996	-45.87183366931264
1997	-47.34273189722837
1998	-44.99660695177754
1999	-41.55554531375464
2000	-44.24315914743955
2001	-44.15830817924239
2002	-42.92727186923034
2003	-42.57524677256602
2004	-45.712289277514145
2005	-44.93842341264278
2006	-42.90532137829461
2007	-36.535262519700765
2008	-32.27260790383084
2009	-33.8730911105269
2010	-29.36773256030704
2011	-29.829706305467454
2012	-25.569707147504552
2013	-23.200136741844645
2014	-9.236258661943443
2015	6.611815932493566