Year	% of total energy use
1971	0
1972	0
1973	0
1974	0
1975	0
1976	0
1977	0
1978	0
1979	0
1980	0
1981	0
1982	0
1983	0
1984	0
1985	0
1986	0
1987	0
1988	0
1989	0
1990	0
1991	0
1992	0
1993	0
1994	0
1995	1.828831172968983
1996	1.7018731695616713
1997	1.7911860691063997
1998	1.7170589628322237
1999	1.7537351372192922
2000	1.660601908526975
2001	1.6275863373749841
2002	1.6423970719707643
2003	1.549517882499969
2004	1.8127534182853084
2005	1.8642988681734556
2006	1.8782232753784538
2007	2.2187223394957654
2008	2.226072555266102
2009	2.4699143530425474
2010	2.8647714548553376
2011	3.521215407366868
2012	4.229909055676285
2013	5.285149050760599
2014	5.2269618874993915