Year	% of total fuel combustion
1990	19.203629032258064
1991	19.294003868471954
1992	12.957746478873238
1993	40.65040650406504
1994	23.88059701492537
1995	15.133531157270031
1996	18.75
1997	26.89873417721519
1998	29.573170731707314
1999	35.153583617747444
2000	21.052631578947366
2001	23.121387283236995
2002	27.491408934707906
2003	30.275229357798167
2004	31.79190751445087
2005	32.92978208232446
2006	34.69879518072288
2007	24.375
2008	25.426944971537008
2009	22.4824355971897
2010	12.839506172839506
2011	12.84796573875803
2012	12.316176470588234
2013	12.595419847328243
2014	11.11111111111111