Year	% of total energy use
1971	1.3511660591656478
1972	1.410645792582483
1973	1.6947297883548695
1974	1.7485933738387318
1975	1.9825698861951502
1976	0.9038063092594966
1977	0.9167393091081169
1978	1.0280378486732271
1979	1.0658219289121558
1980	1.1213973439297384
1981	1.1140461472443741
1982	1.197733518969595
1983	1.067446156330569
1984	1.0985895135989934
1985	1.208084947092428
1986	1.194329204643632
1987	1.166167561290727
1988	1.1206640630736489
1989	1.1103085952359653
1990	0.7422417661540847
1991	0.7386782062074279
1992	0.8021659615232551
1993	0.8206239316457296
1994	0.8136442131031747
1995	0.8183853220711395
1996	0.816588672310686
1997	0.9503840748832643
1998	1.0959752932882891
1999	0.8803349600757385
2000	0.8734050834221692
2001	0.9339559268431423
2002	1.0020533193502232
2003	1.0283462125115141
2004	1.1785932177710277
2005	1.6096252187903073
2006	2.0629685341489687
2007	1.7769573847842872
2008	2.145971879898682
2009	1.9494333107207633
2010	2.2507551575993046
2011	2.3523022268066787
2012	2.017801528448072
2013	2.546606881691036
2014	2.5488400192901888