Year	kg per kg of oil equivalent energy use
1971	2.2250253184555495
1972	2.205860005094627
1973	2.2301546153325384
1974	2.2112055692775474
1975	2.3044986010775963
1976	2.327862584820437
1977	2.3560511802407316
1978	2.4016098238590087
1979	2.399112180950674
1980	2.3604713043973318
1981	2.344661302749778
1982	2.449722370232256
1983	2.4933261468464374
1984	2.5556089775512176
1985	2.685222642739116
1986	2.7170468440409326
1987	2.778398404904553
1988	2.846821261647176
1989	2.833894551418527
1990	2.365438263004016
1991	2.525196453609168
1992	2.557375201400806
1993	2.6281565065388737
1994	2.643356147321915
1995	2.737200345632078
1996	2.666471645862524
1997	2.7134530527277527
1998	2.773342942069035
1999	2.6752677004355814
2000	2.715509093663882
2001	2.763610699285977
2002	2.7889087767335723
2003	2.851700685402644
2004	2.9045420113179388
2005	2.9849439192925438
2006	3.0294027314451997
2007	3.057107667818134
2008	3.051843274793218
2009	3.0529305551219967
2010	3.0491619230203906
2011	3.141495021449401
2012	3.1070513423058146
2013	3.117572828491519
2014	3.077007057545288