Year	% of total energy use
1990	0.0037962881029650155
1991	0.0036244738742638393
1992	0.0037354892880386965
1993	0.004889713109874159
1994	0.0054264587943568515
1995	0.007060044702404615
1996	0.005818518229377347
1997	0.0073177924890890055
1998	0.01131578087902307
1999	0.006914843857590745
2000	0.009694134045134549
2001	0.011137482269165866
2002	0.00987991162014198
2003	0.00932574370134639
2004	0.009526283746491988
2005	0.010628640266546517
2006	0.009724888114448906
2007	0.010006268556008299
2008	0.01089600915429969
2009	0.016977317401804623
2010	0.016393939314667115
2011	0.018380099748390118
2012	0.030648547297923157
2013	0.06622957478899295
2014	0.05392106197090012