Year	% of total fuel combustion
1981	18.11594202898551
1982	18.750000000000004
1983	21.27659574468085
1984	22.857142857142858
1985	22
1986	21.965317919075144
1987	23.463687150837988
1988	21.395348837209305
1989	22.362869198312236
1990	23.131672597864767
1991	26.007326007326004
1992	24.545454545454547
1993	24.615384615384617
1994	25
1995	27.89968652037618
1996	30.82191780821918
1997	31.596091205211728
1998	28.26086956521739
1999	29.274611398963728
2000	30.272952853598014
2001	33.850129198966414
2002	31.017369727047146
2003	34.271099744245525
2004	36.77581863979849
2005	35.046728971962615
2006	39.608801955990224
2007	39.81481481481482
2008	45.10250569476082
2009	39.06581740976646
2010	59.32721712538226
2011	52.86458333333333
2012	41.922290388548056
2013	40.64885496183206
2014	32.122093023255815