Year	% of total fuel combustion
1990	3.861239431709229
1991	3.6657971459260406
1992	2.138716063348417
1993	1.952308472856417
1994	1.916987382471865
1995	1.6603067903262496
1996	1.4280312945350888
1997	1.5934420189739351
1998	1.4948268546623573
1999	1.2438960010558269
2000	1.2983050847457636
2001	1.2451335749765076
2002	1.3255813953488358
2003	1.2532385370850154
2004	1.656503733655067
2005	2.728540809036165
2006	1.5289201379676316
2007	1.354291838524244
2008	1.4925879439601089
2009	1.651699807568955
2010	1.611146580538551
2011	1.717598225148503
2012	1.694481977869482
2013	1.8262772620934273
2014	1.8686057326456407