Year	kg per kg of oil equivalent energy use
1971	5.112362778978742
1972	5.138238398015436
1973	5.1579613201295995
1974	4.707383408153984
1975	4.412580562229952
1976	4.626173361372884
1977	4.382940438511235
1978	4.439378352243288
1979	4.03957778209355
1980	3.6515103137322065
1981	3.079002568406362
1982	2.901407245802035
1983	3.2325200804654757
1984	3.17738504275158
1985	3.0823822126773135
1986	3.0428448758014506
1987	3.1315737853020154
1988	3.239786004782108
1989	3.054470550490804
1990	2.810769266053792
1991	2.8459150598035077
1992	2.8415219993196756
1993	2.7764855396482475
1994	2.783240220776235
1995	2.777975291085237
1996	2.851618886789356
1997	2.76767245349011
1998	2.726489337943672
1999	2.702809629170874
2000	2.8011194701645223
2001	2.7303829077188952
2002	2.743360693534173
2003	2.7609158553161417
2004	2.7351609850569965
2005	2.7289243047909033
2006	2.7680567674064926
2007	2.7688779041709437
2008	2.721076995928099
2009	2.7800151992363946
2010	2.7917748637659723
2011	2.7890001674865155
2012	2.803544291870522
2013	2.8155848122344262
2014	2.797844751339694