Year	% of energy use
1971	-3.4682234010208464
1972	-12.889980520643233
1973	20.795941541546487
1974	27.018278516693783
1975	6.355606225708195
1976	98.63909646547594
1977	98.79262477186742
1978	98.90930666269263
1979	98.87039916987203
1980	98.03822063147129
1981	97.93853266481268
1982	99.00084570817039
1983	99.0754408240031
1984	99.26432899656457
1985	96.27388623766856
1986	96.22581549987802
1987	96.36029339377797
1988	96.51565493535512
1989	96.52660268301628
1990	96.30119881187211
1991	96.19160745974604
1992	96.53607320841009
1993	96.37860705777786
1994	96.50858121480296
1995	96.46788515992844
1996	96.50705404090368
1997	96.52687762444567
1998	96.51564393335072
1999	96.41869521058867
2000	96.4790467999825
2001	96.48646934701642
2002	96.23412585157998
2003	96.25639922280534
2004	91.06709313261213
2005	88.74592966241958
2006	87.01711200183281
2007	85.52670713018784
2008	82.90800562077175
2009	84.80142903580571
2010	83.36523197509733
2011	79.66931640102783
2012	86.59501601677016
2013	71.83296449383593
2014	67.0487382754257
2015	64.96736332553556