Year	kg per kg of oil equivalent energy use
1971	3.453926750961649
1972	3.2667245872213004
1973	3.389999160086689
1974	3.230783356609393
1975	3.3452244834519136
1976	3.4326792061532374
1977	3.352393648227662
1978	3.2798964899970158
1979	3.3365889664447543
1980	3.2689657557782485
1981	3.448670420448842
1982	3.2938367582359924
1983	3.2345094166608486
1984	3.226917129410767
1985	3.3563451108661586
1986	2.9966350601745204
1987	2.9302710951351822
1988	2.9987421783518435
1989	2.9914408360055735
1990	2.68263742704881
1991	2.744028895893953
1992	2.6716332232982904
1993	2.6262341583920152
1994	2.674609511592285
1995	2.6549096537305195
1996	2.599675555556827
1997	2.5140411927938757
1998	2.3389569875231833
1999	2.3190801524225755
2000	2.421847390227584
2001	2.4626950145829576
2002	2.324796823733884
2003	2.2915235399506546
2004	2.3276066353810543
2005	2.282964521876312
2006	2.2782387953674115
2007	2.2565672913878347
2008	2.2596299936132067
2009	2.2915787953343125
2010	2.296813396390312
2011	2.292869945298839
2012	2.2733092929180314
2013	2.2652671497199903
2014	2.1832021246863467
2015	2.1962136712868907