Year	% of total fuel combustion
1990	13.884992987377279
1991	13.491321068496
1992	13.486122307958079
1993	14.107498341074983
1994	13.357287923761913
1995	14.313312258517739
1996	14.5649541601799
1997	11.92644784327204
1998	10.623556581986142
1999	10.965236686390533
2000	11.494914603722894
2001	10.37328094302554
2002	10.102402520677431
2003	9.772240607358382
2004	8.887256702166727
2005	9.052899472823123
2006	8.789096627642843
2007	8.704235463029432
2008	8.145106091718002
2009	8.710427472724021
2010	8.787170063481456
2011	9.151589671526436
2012	9.674627898926964
2013	9.35782967032967
2014	8.932613616576702