Year	% of total fuel combustion
1990	11.171259842519685
1991	14.227086183310536
1992	11.73974540311174
1993	12.618083670715249
1994	13.867047891350964
1995	14.952638700947226
1996	15.085324232081913
1997	15.375153751537512
1998	14.472190692395003
1999	15.535097813578828
2000	15.01787842669845
2001	15.71830985915493
2002	15.59681697612732
2003	15.659068384539149
2004	15.969387755102037
2005	15.770969362129584
2006	14.471707561342015
2007	12.25259189443921
2008	13.095238095238097
2009	14.16579223504722
2010	15.241228070175438
2011	14.03899721448468
2012	13.833028641072517
2013	13.39622641509434
2014	12.351387054161162