Year	% of total energy use
1971	1.2644366447742272
1972	1.3725300228337283
1973	1.5104925487370469
1974	1.6909359571785902
1975	1.831650037310104
1976	1.9771049309172986
1977	1.8512583023069091
1978	1.8791330991046677
1979	2.016172302305461
1980	1.690375150030097
1981	1.7064647078431356
1982	1.6891952815671352
1983	1.7785096403570206
1984	1.917698135916857
1985	1.8595811776131297
1986	2.2026434193932665
1987	2.099200919558764
1988	2.25421430159923
1989	2.2088078445369326
1990	1.4600200941347519
1991	1.4657480992734564
1992	1.5624296841977892
1993	1.4636977779869011
1994	1.556626366556156
1995	1.5149237134946087
1996	1.3969621142007242
1997	1.3693355282681545
1998	1.2781382103858077
1999	1.2161053364479126
2000	1.3267397526981728
2001	1.3616540794832717
2002	1.448166479652495
2003	1.6519003186186554
2004	1.7311625642252442
2005	1.7934758957647154
2006	1.798798813390097
2007	1.7288417781253245
2008	1.6401809835118062
2009	1.6929220619038463
2010	1.901795489680501
2011	1.8745024408689903
2012	1.8202133967485508
2013	1.918289076983411
2014	1.8999329183303175