Year	% of total fuel combustion
1990	40.77052552833364
1991	43.178324365872406
1992	54.21970768505422
1993	59.8661311914324
1994	50.76645626690711
1995	47.682323856613095
1996	54.69327420546932
1997	54.37928408225437
1998	60.4952380952381
1999	61.76242236024845
2000	59.743589743589745
2001	58.61401471157569
2002	54.80203841630733
2003	58.519051042415526
2004	57.22627737226278
2005	56.77352637021716
2006	57.70670296019055
2007	54.439865118021736
2008	48.47222222222222
2009	47.10440456769983
2010	42.49893752656184
2011	44.06202723146747
2012	48.39044652128764
2013	46.6893039049236
2014	46.183825917505686