Year	% of total fuel combustion
1990	65.46511627906978
1991	67.69964243146602
1992	68.10551558752998
1993	68.32369942196532
1994	71.05263157894738
1995	72.95673076923076
1996	66.76798378926038
1997	68.97727272727272
1998	72.15320910973084
1999	70.52868391451068
2000	71.98124267291911
2001	75.23041474654377
2002	71.49877149877149
2003	69.11764705882354
2004	69.70760233918128
2005	68.98876404494382
2006	68.31460674157303
2007	66.4882226980728
2008	68.23658269441401
2009	70.18779342723006
2010	63.78896882494004
2011	65.06550218340611
2012	64.81271282633371
2013	60.864040660736975
2014	59.89232839838492