Year	kg per kg of oil equivalent energy use
1971	3.7105933574501186
1972	3.71743140635521
1973	3.5282626266824075
1974	3.465443436253705
1975	3.431476638147463
1976	3.4586631438245763
1977	3.508341778539994
1978	3.3561786295017693
1979	3.5202397274245585
1980	3.494123340263845
1981	3.5784244478615284
1982	3.589404198984769
1983	3.669307245219821
1984	3.6565124382164647
1985	3.752475191717137
1986	3.67703389089656
1987	3.528859426067004
1988	3.5362522588687617
1989	3.671713376183479
1990	2.722853090916511
1991	2.5513586613946657
1992	2.695909674450563
1993	2.595695426283119
1994	2.5671193843142945
1995	2.551486568082907
1996	2.589367338303706
1997	2.6586983750035897
1998	2.7464878098031025
1999	2.548585599057231
2000	2.6112108683598114
2001	2.858617716384053
2002	3.012084792831649
2003	3.0012451457339484
2004	2.957934285251499
2005	2.9445437247667208
2006	2.981070672470827
2007	2.91115643455936
2008	2.904592504894333
2009	2.806371501057766
2010	2.998517246587962
2011	2.8958582566286344
2012	3.0631773967069567
2013	3.126321724661317
2014	3.0469821480976567