Year	% of total fuel combustion
1990	9.23882550963157
1991	8.916218293620291
1992	8.486562942008485
1993	6.318607764390896
1994	14.156898106402164
1995	11.928306551297899
1996	15.077605321507761
1997	15.536938309215536
1998	16.952380952380953
1999	18.439440993788818
2000	15.714285714285714
2001	18.041037553232677
2002	20.42336338690709
2003	20.596693026599567
2004	20.583941605839414
2005	19.924164081351257
2006	19.734603606668934
2007	20.457100037467217
2008	23.020833333333332
2009	24.306688417618272
2010	25.92435189120272
2011	23.335854765506806
2012	18.033921772239527
2013	17.147707979626485
2014	18.220201364079248