Year	% of energy use
1960	12.335653942186566
1961	12.586700771082118
1962	17.941880543194703
1963	18.02619834503623
1964	19.24357063385389
1965	18.820090522768627
1966	19.350595763955873
1967	16.25670021039854
1968	18.0882742089527
1969	19.435914726701185
1970	23.184991572491263
1971	-45.43373230218173
1972	-45.3826582469369
1973	-49.344330563699785
1974	-45.79203664331982
1975	-39.88550136043682
1976	-43.7784162102366
1977	-41.00202494171001
1978	-38.24770392946142
1979	-35.61860669329859
1980	-26.31357050628879
1981	-18.341545901389914
1982	-20.45322092455597
1983	-22.126654793182478
1984	-23.876562030803758
1985	-24.025674134479225
1986	-22.200466708433087
1987	-22.3296226568577
1988	-23.7546657183822
1989	-25.98462381160132
1990	-21.99549201612647
1991	-19.423232140509043
1992	-20.15689804800663
1993	-19.338781152376896
1994	-20.89380755918638
1995	-20.44987226683498
1996	-20.915486333773213
1997	-21.568024511831723
1998	-23.305702019758023
1999	-22.494618991301746
2000	-23.7107359549907
2001	-23.79903927056382
2002	-22.947854246448372
2003	-23.111941915490437
2004	-22.268730174391177
2005	-21.89091880234242
2006	-20.685270181381796
2007	-19.301666299421758
2008	-18.155286870809082
2009	-16.075601905577766
2010	-14.907527158646623
2011	-13.236189691954879
2012	-10.744490652798195
2013	-9.911723000922924
2014	-8.157825540831857
2015	28.00817540414526