Year	% of total fuel combustion
1971	8.126822157434402
1972	7.662968099861304
1973	7.704654895666131
1974	7.363723302518331
1975	7.827476038338659
1976	7.74193548387097
1977	8.291382884216759
1978	8.960047003525265
1979	9.019370460048425
1980	10.180337405468297
1981	10.524781341107873
1982	10.42540443379269
1983	9.117137911136759
1984	9.597615499254845
1985	9.958871915393654
1986	10.758017492711371
1987	11.120789779326365
1988	10.855263157894738
1989	11.718538565629228
1990	11.137884872824632
1991	10.54139215124606
1992	10.788499857671507
1993	10.83501878069922
1994	10.95302013422819
1995	11.222739524626316
1996	12.708480150340616
1997	12.627912040060963
1998	11.351679481991097
1999	10.984555984555985
2000	10.361626381862468
2001	10.736358820413209
2002	10.468319559228648
2003	11.721208307111391
2004	10.685572284753691
2005	10.388349514563108
2006	9.752942698227915
2007	9.006873666745676
2008	9.134287661895025
2009	8.714007360900629
2010	8.463661453541857
2011	7.773068772876132
2012	7.769312544294826
2013	7.351831670718417
2014	7.275750138548016