Year	kg per kg of oil equivalent energy use
1971	0.7493839939589537
1972	0.48091008534402646
1973	0.5113750287262856
1974	0.4995448366678062
1975	0.4706961122975284
1976	0.446444286846988
1977	0.4478857125756371
1978	0.4710335775121398
1979	0.49509777285245277
1980	0.49757586013447
1981	0.4892880657917988
1982	0.4765526392030678
1983	0.4742010438015354
1984	0.48158081952782766
1985	0.47328598874677436
1986	0.4773582546388966
1987	0.46795303714280595
1988	0.4799803499996445
1989	0.470305575816141
1990	0.4702502479755396
1991	0.44943058690701543
1992	0.4430745747816767
1993	0.43373163518392216
1994	0.44389120706463525
1995	0.5202824690703015
1996	0.5302350657137768
1997	0.5528929026781976
1998	0.5516606358804016
1999	0.5756000247936075
2000	0.586327318380925
2001	0.6089322661381928
2002	0.6166564818341108
2003	0.6696587224609981
2004	0.7105589770100973
2005	0.7224475988152278
2006	0.7369683227765053
2007	0.7720598524434514
2008	0.7684136189941123
2009	0.7982396050911226
2010	0.8199879802237353
2011	0.8266851661498891
2012	0.8404040158938124
2013	0.8781912295134523
2014	0.8461647855329515