Year	kg per kg of oil equivalent energy use
1971	3.3798162339744016
1972	3.4098031496265864
1973	3.356895898408645
1974	3.333392007724625
1975	3.1431269914145044
1976	3.0025000194030738
1977	2.9207811024300168
1978	2.994544710659082
1979	2.802104313131412
1980	2.729495289057136
1981	2.836730333063138
1982	3.054289764865838
1983	2.999388643824204
1984	2.8784092541063724
1985	2.9220650113472937
1986	2.960728050341776
1987	2.994404640172768
1988	2.7861318350931903
1989	2.8513062907142364
1990	2.60627626471717
1991	2.6765927873473747
1992	2.6942236928946635
1993	2.536983125575971
1994	2.5154324033941418
1995	2.368693947893844
1996	2.3978857145719026
1997	2.5640855640685567
1998	2.525645990500795
1999	2.418767495455802
2000	2.328757581763952
2001	2.381480723027449
2002	2.3090575335317443
2003	2.4731710773358375
2004	2.5049741097811538
2005	2.4063670421396686
2006	2.393702173004495
2007	2.6157356132552874
2008	2.520809654030842
2009	2.454480160294634
2010	2.5093754687594503
2011	2.5827399756462235
2012	2.4572124003615894
2013	2.353240832806139
2014	2.359424952882736