Year	% of total energy use
1990	0.1423642608779774
1991	0.27149796195940357
1992	0.2446231796880546
1993	0.3877849373476131
1994	0.3763549205054362
1995	0.5574294538094848
1996	0.7168835908910322
1997	0.839132093848779
1998	0.8337916898601562
1999	0.9347572553777418
2000	1.0957307714053708
2001	1.1963484698710347
2002	1.2706370178174784
2003	1.1665961524096025
2004	1.0638087713302697
2005	1.0403821073234616
2006	1.0774066203760864
2007	1.0422487159232665
2008	1.0881836891620238
2009	0.8788572635438194
2010	0.9077012692745573
2011	0.7094570883551297
2012	0.565254640981761
2013	0.8778337599590335
2014	0.7672380689299224