Year	% of total energy use
1990	0.42964017209947075
1991	0.46499467284270396
1992	0.593553264549658
1993	0.900095468792868
1994	0.7547943529790866
1995	0.7250735380269115
1996	0.8091549868113622
1997	0.9419484005608368
1998	1.0579792204216143
1999	0.9250930665319337
2000	0.9022167072293965
2001	0.7766407595951391
2002	1.164276536268628
2003	1.3506155951314964
2004	1.443855293624906
2005	1.5193900852261513
2006	1.3094546130855103
2007	1.2172151202547148
2008	1.0362064768767734
2009	1.0812856781319498
2010	1.6732289274846632
2011	1.1977317875430227
2012	0.7659495625682528
2013	0.660788427016893
2014	0.5720463016272235