Year	% of total fuel combustion
1990	38.82874015748031
1991	38.16689466484268
1992	43.7057991513437
1993	44.93927125506073
1994	38.813438170121515
1995	41.13667117726658
1996	40.4778156996587
1997	38.92988929889298
1998	42.111237230419974
1999	39.010356731875724
2000	36.829558998808096
2001	37.74647887323944
2002	39.89389920424403
2003	40.58473736372646
2004	36.32653061224489
2005	35.710698141637366
2006	34.60190285428143
2007	37.88878416588125
2008	34.42460317460318
2009	34.15529905561386
2010	33.05921052631579
2011	35.20891364902508
2012	34.36928702010969
2013	32.83018867924528
2014	31.770145310435932