Year	% of total fuel combustion
1990	19.403988348644408
1991	19.37533086289042
1992	9.985528219971055
1993	18.181818181818183
1994	32.11544365980964
1995	33.62406015037594
1996	29.084745762711865
1997	34.15126050420168
1998	32.30263157894737
1999	32.43395165823496
2000	20.840152755046372
2001	19.371865927685405
2002	18.2527693856999
2003	20.30755314337404
2004	21.528224940974454
2005	21.14784778540237
2006	21.849593495934958
2007	25.67180222142601
2008	23.830616583982994
2009	26.69203043652383
2010	26.959578207381373
2011	26.22207834250566
2012	26.076779026217228
2013	25.86654451061231
2014	25.82089552238806