Year kg per kg of oil equivalent energy use 1990 3.086180451892431 1991 2.9815229206998533 1992 2.9681817345224366 1993 2.855626823209472 1994 2.77811505482946 1995 2.5730811205153623 1996 2.5647671524352096 1997 2.4750077182521486 1998 2.420798606067781 1999 2.3590810175823753 2000 2.327490788027332 2001 2.300083582809398 2002 2.3194121227078845 2003 2.312447006422769 2004 2.3039741481070397 2005 2.3390241008125106 2006 2.312790076913312 2007 2.4245846930666413 2008 2.4365684983682465 2009 2.40474048632414 2010 2.3665069131939602 2011 2.4188630764172436 2012 2.383256306918909 2013 2.3388947777496183 2014 2.3352830372127804