Year	kg per kg of oil equivalent energy use
1990	3.234482103417327
1991	3.30274309806349
1992	3.242467674030495
1993	3.327324846519046
1994	3.372316330840022
1995	3.3014793912307825
1996	3.305211911269326
1997	3.210821295728567
1998	3.312888095612513
1999	3.291899569141152
2000	3.214209969583562
2001	3.238955904454188
2002	3.056625894709833
2003	3.162166622841775
2004	2.957666153718388
2005	3.1934945795205607
2006	2.9336760171668153
2007	2.861555952853494
2008	3.3209921328371657
2009	3.2173433934629325
2010	3.2344870596429316
2011	3.131670348578612
2012	3.2692335757124793
2013	3.143646584662956
2014	2.676890755453058
