Year	kg per kg of oil equivalent energy use
1971	3.3665366077576313
1972	3.553992550451235
1973	3.5852841557968307
1974	3.434112921112946
1975	3.3099973186149185
1976	3.0484835216130057
1977	3.1949119602955625
1978	2.9970887834621176
1979	3.0423338952522263
1980	3.1050039249690435
1981	3.0928074368321306
1982	2.9180533734490557
1983	3.14482848162924
1984	3.243631983616863
1985	3.2629353968482593
1986	3.305497898710734
1987	3.24524718340725
1988	3.156500642369695
1989	3.1068418444066617
1990	3.033023301132787
1991	2.8900811705006046
1992	3.1354666255618917
1993	3.2396361516840133
1994	3.2174131651394893
1995	3.1616760230579177
1996	3.1427024839585087
1997	3.1871431929984877
1998	3.1336095170788156
1999	3.1477048111258776
2000	3.3438279246008937
2001	3.373333106368562
2002	3.334085001182839
2003	3.3460163655187505
2004	2.9880562983257395
2005	2.9761695245333275
2006	2.9429775841991432
2007	2.925523171350348
2008	2.8306799304510006
2009	2.7701874730406186
2010	2.843763092572654
2011	2.9380496105810545
2012	3.0726748755834197
2013	3.079948075698912
2014	3.1285068097898425