Year	% of energy use
1971	7.139542838522026
1972	5.142730062891076
1973	1.3136104001608593
1974	4.569734990049999
1975	2.9561624089587717
1976	1.8712608607613674
1977	0.4891965756577726
1978	-0.13726561903891543
1979	-0.4213481307524246
1980	-0.9834374078312688
1981	-0.8909956732514343
1982	-0.020870650555399772
1983	-1.1056064814786768
1984	-2.053582742884495
1985	-0.983187801571189
1986	-0.029802951732139617
1987	-1.4690233911332622
1988	0.20973065388172102
1989	0.20428975575461594
1990	0.2397042308794011
1991	0.19541083077456944
1992	0.20282967765495358
1993	3.175987347296036
1994	4.058314229811053
1995	6.860511721203482
1996	7.786740693765718
1997	7.51948146770902
1998	1.9921375779591026
1999	-9.851501979017858
2000	-20.06401226204769
2001	-26.40162923429477
2002	-26.829877786286538
2003	-30.37985055619295
2004	-36.43497976085933
2005	-49.55207007481163
2006	-50.49539968043939
2007	-50.719291654233935
2008	-50.04778763943355
2009	-54.0043312798301
2010	-60.89373653102551
2011	-58.24636825701119
2012	-46.28353535839339
2013	-39.81980164118334
2014	-32.970794069021416