Year	kg per kg of oil equivalent energy use
1971	3.736175528922207
1972	3.9235477852863663
1973	3.8354200085695216
1974	3.65204959515126
1975	3.6634962562034934
1976	3.9794666156070155
1977	3.815529926147339
1978	3.6228726949037973
1979	4.1381676347859315
1980	4.658905963197966
1981	4.996053361582376
1982	3.8291805319678422
1983	3.812906557530405
1984	3.9203560508419986
1985	3.7859029155220636
1986	3.8976206163523575
1987	4.049650803445518
1988	3.9875137854879856
1989	3.7166863315644783
1990	2.8255262841309863
1991	2.816133577521027
1992	2.8784618086787277
1993	2.805660063453888
1994	2.786884787315583
1995	2.7847513660904073
1996	2.881795421961473
1997	2.678592930447
1998	2.591435619098175
1999	2.5528436357926614
2000	2.5601112900389777
2001	2.6072172318246656
2002	2.551066903688871
2003	2.5558465776319657
2004	2.5843342953249753
2005	2.674129218637238
2006	2.7199029767195166
2007	2.7437208786072675
2008	2.773094867376283
2009	2.7527173428776996
2010	2.7562545741360456
2011	2.8111899839593257
2012	3.0979428891298175
2013	2.6236161026608174
2014	2.5059204337399277