Year	% of total fuel combustion
1990	27.671969527223844
1991	24.69560614081524
1992	42.61939218523878
1993	21.2375859434683
1994	18.483266809947803
1995	16.8421052631579
1996	21.355932203389834
1997	21.98319327731092
1998	24.50657894736842
1999	22.034851039910063
2000	21.11292962356793
2001	20.98178939034046
2002	22.2306143001007
2003	22.41067390321122
2004	21.785790942262288
2005	20.44084009149511
2006	19.532520325203254
2007	18.255105696882833
2008	17.983699503897945
2009	18.422106527833403
2010	17.943760984182784
2011	17.821301392036258
2012	18.008739076154807
2013	17.727897388914336
2014	17.283582089552237