Year	% of total fuel combustion
2000	6.153846153846153
2001	7.8125
2002	7.462686567164178
2003	9.589041095890412
2004	9.090909090909092
2005	8.21917808219178
2006	9.589041095890412
2007	11.249999999999998
2008	13.095238095238097
2009	14.953271028037381
2010	15.441176470588234
2011	14.49275362318841
2012	16.042780748663098
2013	14.04494382022472
2014	14.285714285714288