Year	kg per kg of oil equivalent energy use
1971	2.831058313942396
1972	3.062836027947541
1973	2.487258969135478
1974	3.3229178984148637
1975	2.7975542776007694
1976	3.0296894212077623
1977	3.0820711804641046
1978	3.103172157426648
1979	2.7678715197899395
1980	2.7032582129617793
1981	2.913175442453662
1982	3.050577934364128
1983	3.2506808074361255
1984	3.122176982348472
1985	3.2840585340499837
1986	2.9461604383043865
1987	2.750984160609547
1988	2.759344134948724
1989	2.824041285710678
1990	2.9479051950200637
1991	3.0006575890689833
1992	2.787713429109869
1993	2.921862893206993
1994	2.932777440340029
1995	3.016404480686014
1996	3.056230501870303
1997	3.0313546265626243
1998	2.9888559779411983
1999	3.159469669478802
2000	3.1259436099515567
2001	3.0271494824697487
2002	3.247456159341849
2003	3.187542178927604
2004	3.2870192870904815
2005	3.30674688595692
2006	3.1640436369474125
2007	3.2000529001086115
2008	2.916462926006362
2009	3.0549414863889384
2010	3.0399710273644818
2011	3.0168360363873115
2012	3.134248913675343
2013	2.896475512396245
2014	2.851173250522561
2015	2.84120283658062