Year	% of total fuel combustion
1971	21.18790390212619
1972	22.503202543056414
1973	23.302251106715644
1974	25.54709383753502
1975	26.063481675392673
1976	27.293453899064843
1977	26.591123701605287
1978	24.146435452793835
1979	25.753327417923686
1980	29.62464231610841
1981	30.71857208801355
1982	32.033202171353075
1983	33.84806435937584
1984	33.0120422221121
1985	36.37242647925854
1986	37.98578917724535
1987	40.495175823299576
1988	40.3575941608042
1989	41.29850982044126
1990	41.944052461193664
1991	43.685075506217245
1992	45.045111560668026
1993	47.26366758628456
1994	46.71175497572168
1995	49.225872512614266
1996	49.84359565360555
1997	49.16292090968914
1998	50.0515599631401
1999	51.14013793383645
2000	52.73859896567936
2001	53.31520642576456
2002	52.47272422869793
2003	53.136689207022386
2004	53.79543789627908
2005	52.75398878480647
2006	52.916698077647936
2007	52.69370564025753
2008	51.42037302725968
2009	50.490781736828545
2010	49.69168354734122
2011	49.89434801816044
2012	51.59734840165325
2013	50.79484945299643
2014	52.129310806230045