Year	% of total fuel combustion
1990	7.929226736566186
1991	9.23139487596584
1992	11.088709677419356
1993	8.411764705882351
1994	9.485879797248371
1995	10.933557611438182
1996	13.614103819784523
1997	14.715359828141782
1998	12.811387900355871
1999	10.084033613445378
2000	10.856269113149846
2001	10.380116959064328
2002	13.793103448275861
2003	15.02659574468085
2004	16.822429906542055
2005	15.454545454545453
2006	15.978695073235686
2007	17.774762550881952
2008	21.69167803547067
2009	20.770288858321873
2010	22.038216560509554
2011	23.58974358974359
2012	21.231979030144167
2013	25.671641791044774
2014	24.689655172413794