Year	kg per kg of oil equivalent energy use
1971	1.8550820730943642
1972	1.7278536217783287
1973	1.798259860946798
1974	1.4581625444666164
1975	1.5675459825419604
1976	1.1154036196706982
1977	1.1778789127386873
1978	1.1588650983440194
1979	1.1828936004008106
1980	1.168754910770245
1981	1.2162665935518433
1982	1.2173780969343813
1983	1.239327426383932
1984	1.1126417226048715
1985	1.3256456548842068
1986	1.3803631790432942
1987	1.467124582151273
1988	1.29756094448447
1989	1.0026439909730733
1990	1.030446417262065
1991	1.0111253609899773
1992	1.0216290131211871
1993	1.1824699344219243
1994	1.3034433074033387
1995	1.3854089931138045
1996	1.4784402139891857
1997	1.6116931671878705
1998	1.6905657988780551
1999	1.6537346835501616
2000	1.7507626048382643
2001	1.8247354043927895
2002	1.9819759798147047
2003	2.0067943917530378
2004	2.1674347724285874
2005	2.2311784498415013
2006	2.265372489833147
2007	2.31681323987754
2008	2.418419366172625
2009	2.4823215156272713
2010	2.5366679132166934
2011	2.5308032999283827
2012	2.457490110133336
2013	2.5635928465897684