Year	% of total energy use
1971	0.02120234370425548
1972	0.15526458178801703
1973	0.17223143008284308
1974	0.19088938862688898
1975	0.17846466250529516
1976	0.2889502308945818
1977	0.2933418948703103
1978	0.27235117302544654
1979	0.15820976987460786
1980	0.13048163740750948
1981	0.19765506275900702
1982	0.11171102030314808
1983	0.06425010757529738
1984	1.2395262830357168
1985	1.6652589711293655
1986	2.7047406303311865
1987	1.8728547601787715
1988	3.099104855670517
1989	3.368877791745844
1990	2.500760892643727
1991	2.6572665196235628
1992	2.7880401185947394
1993	2.001502737330043
1994	2.645497152296433
1995	2.8777308272743456
1996	2.989904506801507
1997	3.1724864913377853
1998	3.389517827485627
1999	3.1093365360928162
2000	3.18211165476412
2001	2.6238015064665703
2002	3.0053422234822413
2003	2.8595419286169084
2004	2.775104634872139
2005	2.3805263071714893
2006	2.2222764817855687
2007	2.222001574151548
2008	2.398507816670668
2009	2.426836698845518
2010	2.3736760332447404
2011	2.643181356952661
2012	2.354825509402826
2013	2.7687404681877
2014	2.664953567530257