Year	% of total fuel combustion
1990	41.09505571030641
1991	39.75913761158834
1992	43.405901403382515
1993	42.002496433666195
1994	39.242410000939934
1995	37.825259149566314
1996	39.709265843965696
1997	39.482100484886
1998	36.63946061036196
1999	35.70487483530962
2000	36.37241137241138
2001	36.57860545690775
2002	36.19652406417112
2003	36.611260986859286
2004	36.93323812923955
2005	37.829008773567296
2006	37.919064583904266
2007	37.73430391264786
2008	35.111844517785116
2009	39.568635355775044
2010	40.593447352153305
2011	38.676122931442066
2012	37.60223048327138
2013	42.30968947969675
2014	42.451481103166486