Year	% of total fuel combustion
2000	33.84615384615384
2001	31.25
2002	34.32835820895522
2003	32.87671232876712
2004	33.76623376623377
2005	34.24657534246575
2006	30.136986301369863
2007	25
2008	26.190476190476193
2009	22.429906542056074
2010	24.264705882352942
2011	27.536231884057973
2012	22.994652406417114
2013	21.34831460674157
2014	23.46938775510204