Year	% of total fuel combustion
1960	19.34765726119596
1961	19.61933533603755
1962	19.54747821035324
1963	19.378241331559373
1964	19.482132729231125
1965	19.14382363233407
1966	19.300773083021614
1967	19.438224678531057
1968	19.77150575914526
1969	19.660146190797736
1970	19.32733909982837
1971	19.53764843529364
1972	19.81287712959403
1973	19.86352038736815
1974	20.002025151547098
1975	21.16751670037583
1976	20.977714022234743
1977	21.257559523092915
1978	22.020240831452824
1979	21.68253177562092
1980	21.905594158615862
1981	22.27002673993319
1982	22.8489263021345
1983	23.342442811518186
1984	23.34270281608894
1985	23.410997766644538
1986	24.07478105466169
1987	24.41663273615635
1988	24.879355036951825
1989	25.08875153743777
1990	24.117953883233206
1991	24.282090437776056
1992	24.80696445528854
1993	25.168908631633297
1994	25.723194446330062
1995	25.996463102755186
1996	26.01744160659798
1997	26.182803643663473
1998	26.70832345145995
1999	27.203476245256187
2000	26.77026136705156
2001	26.817161634633763
2002	27.214305040052203
2003	27.026911498997944
2004	27.180347196480685
2005	27.28881795556848
2006	27.581185007281746
2007	27.47168734845243
2008	27.118575865667953
2009	27.822549971585442
2010	27.21763682632103
2011	27.35406604453963
2012	27.890157901785674
2013	27.845600038227452
2014	28.65809256505643