Year	kg per kg of oil equivalent energy use
1971	2.5448358962588933
1972	2.6186038465216104
1973	2.56063742358287
1974	2.5692227728710164
1975	2.552909113162906
1976	2.5228295681242248
1977	2.6853933075374643
1978	2.711052205899648
1979	2.922532496502376
1980	2.9051530643625845
1981	2.9168238041486667
1982	2.871430328180138
1983	2.99775010195472
1984	2.8898041870364786
1985	2.8686735304830524
1986	2.9393708157973855
1987	2.8174594667313175
1988	2.8452396958748802
1989	3.035181094373098
1990	2.7795005065766016
1991	2.9434139887280715
1992	2.7864003837082585
1993	3.115422832843421
1994	2.9052308463277705
1995	2.9357428937018146
1996	2.9009046042465614
1997	2.9052430528255644
1998	2.7740227141437037
1999	2.814213537246556
2000	2.8648039737691815
2001	2.807631466532903
2002	2.781034903331841
2003	2.7243560796927095
2004	2.6977100660035003
2005	2.7831148876801466
2006	2.7503149379122402
2007	2.7127503803880093
2008	2.62970357862453
2009	2.7397311132448037
2010	2.6688113120251833
2011	2.620890083619845
2012	2.604418080948008
2013	2.570901714244995
2014	2.741674884717469