Year	% of total fuel combustion
1990	6.716906946264745
1991	8.824725498169988
1992	6.048387096774193
1993	7.352941176470589
1994	7.241129616220129
1995	8.32632464255677
1996	6.758080313418216
1997	7.841031149301825
1998	7.117437722419928
1999	6.442577030812326
2000	7.64525993883792
2001	7.309941520467836
2002	7.471264367816093
2003	7.446808510638299
2004	8.678237650200266
2005	12.987012987012985
2006	9.85352862849534
2007	11.668928086838534
2008	9.413369713506139
2009	8.11554332874828
2010	11.974522292993631
2011	13.333333333333334
2012	13.892529488859765
2013	11.940298507462686
2014	12.689655172413794