Year	% of total fuel combustion
1986	15.814587593728696
1987	17.30496453900709
1988	18.547807332854063
1989	18.3585313174946
1990	19.350073855243725
1991	19.450980392156865
1992	20.562248995983936
1993	23.268072289156628
1994	26.077097505668934
1995	27.292110874200425
1996	29.340511440107676
1997	29.823413996075864
1998	25.182724252491695
1999	24.844290657439448
2000	25.10668563300142
2001	24.798387096774192
2002	25.182239893969516
2003	25.78490313961256
2004	26.509186351706038
2005	27.896440129449836
2006	28.779253636938645
2007	32.67766497461929
2008	36.07142857142856
2009	33.5978835978836
2010	33.72168284789644
2011	36.098509397278036
2012	37.52521856086079
2013	37.20112517580872
2014	41.53605015673981