Year	% of total energy use
1971	1.227592215747099
1972	1.3498181125135618
1973	1.3255023485579853
1974	1.5204806808432263
1975	1.656147161380952
1976	1.8075232298691124
1977	1.8873283584345986
1978	1.7828681925184304
1979	1.905216554707382
1980	1.7075106989345425
1981	1.6561211882062012
1982	1.6620902455250797
1983	1.6689021105038786
1984	1.793543488946277
1985	1.878534629158722
1986	1.9318564673706968
1987	2.1315023452757482
1988	2.3134202630217833
1989	2.361847308681424
1990	1.6437850832515484
1991	1.756967648573095
1992	1.811169947629916
1993	1.8254502242344735
1994	1.7315610332161537
1995	1.7168573166069907
1996	1.8938664119817687
1997	1.8457172007420604
1998	1.860851768170228
1999	2.0098307166459026
2000	2.0793565600643706
2001	1.9751433552860316
2002	2.0052185983183994
2003	2.1060932188907424
2004	2.309006557109222
2005	2.4573912007801315
2006	2.4985926167955843
2007	2.4785347906438138
2008	2.3462128222284235
2009	2.351422706473724
2010	2.3161339953967524
2011	2.4494084274440833
2012	2.3440804313521326
2013	2.479951206911276
2014	1.4513889216809044