Year	% of total fuel combustion
1990	20.25
1991	22.543083372147183
1992	26.051475204017578
1993	27.973074046372474
1994	22.475570032573287
1995	23.475609756097562
1996	11.864406779661017
1997	10.332541567695962
1998	6.948356807511737
1999	6.724303554274735
2000	8.017492711370261
2001	8.666666666666666
2002	7.313642756680731
2003	11.20274914089347
2004	10.53324555628703
2005	11.223203026481714
2006	8.013737836290783
2007	8.414766558089031
2008	9.337944664031621
2009	4.255319148936171
2010	4.929233772571988
2011	4.529914529914531
2012	4.5265588914549655
2013	3.0218503021850296
2014	3.0527289546716005