Year	% of total energy use
1971	0.2793441907892982
1972	0.27072126867452845
1973	0.24161801994429813
1974	0.8520731684164562
1975	0.67202787990563
1976	0.7977801955082239
1977	0.800434085124069
1978	1.061649819542255
1979	0.5586408596496992
1980	0.38520483668228606
1981	0.07479909758901848
1982	0.33331822689474033
1983	0.3130538327346092
1984	0.328115806240924
1985	0.5065364404671255
1986	0.2361460607351542
1987	0.2482055603817748
1988	0.23167238707269378
1989	0.4005849353559833
1990	0.4505801051328684
1991	0.697385672476076
1992	0.764218231220496
1993	0.8592887953625603
1994	0.8252922664502308
1995	0.886037546158549
1996	0.8376332059371834
1997	0.9879795005725891
1998	1.179906847314222
1999	1.3007456315175918
2000	2.4778170270318878
2001	5.501944621601527
2002	5.461823248090014
2003	7.422182252649977
2004	8.983893034655077
2005	9.181417616599845
2006	9.086128488035783
2007	8.712897116188515
2008	9.216018484169828
2009	8.531990268818342
2010	8.478807652734616
2011	8.407674123503266
2012	8.901022235137294
2013	8.667001874946484
2014	9.17019673478017