Year	kg per kg of oil equivalent energy use
1971	0.29423772609819127
1972	0.43886917337052106
1973	0.33623381614043474
1974	0.46336825169243323
1975	0.8756565017735859
1976	0.8677875925185987
1977	0.9501178573349861
1978	0.9874129291165035
1979	1.0683519536796524
1980	0.9399289063194121
1981	1.0848688507203583
1982	1.3265449490532462
1983	1.5910184744991591
1984	1.7953685164345323
1985	1.8173653418431486
1986	1.6757994749875125
1987	1.5039271116601352
1988	1.4332517271714862
1989	1.4349730792674673
1990	2.6417934913210717
1991	2.778823923254768
1992	2.7328112755853096
1993	2.807869781235131
1994	2.808562671684985
1995	2.888231582914779
1996	2.888944999130164
1997	2.926497969118299
1998	2.9611797663318655
1999	2.945537745153953
2000	2.9261923285728457
2001	2.8642992638105094
2002	2.9686396747908175
2003	3.0707311146065677
2004	2.9750706862243073
2005	2.9419899693018983
2006	2.7523571932876516
2007	2.9893243590811776
2008	3.0244293090147782
2009	3.1763301610071233
2010	3.0629322130585352
2011	3.127954662345685
2012	3.289777217891574
2013	3.1879194427879765