Year	% of total energy use
1971	1.2866088308257824
1972	1.0341893213383109
1973	1.0359219121960073
1974	1.3260844131382654
1975	1.685729938583086
1976	1.6606428618643116
1977	1.400148806013993
1978	0.8707624589187843
1979	1.2747697634558854
1980	0.49758149522971157
1981	1.1500366530230102
1982	1.4669762695590685
1983	1.5235108124689165
1984	1.538447646245149
1985	1.2831308350334905
1986	1.8381195337240388
1987	1.2208978129607544
1988	0.9926923873887115
1989	1.3082123712997398
1990	0.8855669149437272
1991	0.7489700889937534
1992	0.6486951900817908
1993	0.5519985343210008
1994	0.6022396196321248
1995	0.829179502303083
1996	0.7851461969875467
1997	0.7764441713253052
1998	0.6015591262367953
1999	0.3896289911460033
2000	0.6570542691359788
2001	0.6568248960160447
2002	0.7179180598436984
2003	0.644233272305081
2004	0.4937529569214283
2005	0.4621702986791373
2006	0.6386284967404009
2007	0.6172176082624459
2008	0.5230679851795192
2009	0.528255352151954
2010	0.39558816037953803
2011	1.0122733013208025
2012	1.1092300159727981
2013	0.8998950817593542
2014	1.108075739007851