Year	% of total energy use
1971	1.792079102857616
1972	1.696214535348722
1973	1.9508429461217163
1974	1.7905028936018166
1975	2.064401979211831
1976	2.149665300734992
1977	2.099392877654408
1978	2.562473232000979
1979	2.3905510676479795
1980	2.3928107640194605
1981	2.403857586327361
1982	2.1477958591752233
1983	2.317100573030661
1984	2.429907584538511
1985	2.302770921826323
1986	2.323136269040125
1987	2.0318357912487652
1988	2.320041358382727
1989	2.234266042555465
1990	2.007333266220359
1991	1.906854292090545
1992	1.896743455037715
1993	1.7674020168059512
1994	1.9570822230935518
1995	1.826522377006243
1996	1.76282009840488
1997	1.8480869439481764
1998	2.0323808507175753
1999	1.9204628002644262
2000	1.987974860403714
2001	2.0916876604761625
2002	1.988193896774159
2003	2.0188265728094827
2004	2.020142462706657
2005	2.194685901607131
2006	2.370720003879857
2007	2.3028395365490772
2008	2.0420784936468968
2009	2.020894335248908
2010	2.3520638610376436
2011	2.7043140379010606
2012	2.5260008202855175
2013	2.7206630745404388
2014	2.667720546657545