Year	% of total fuel combustion
1960	19.7376267143709
1961	19.68312004875076
1962	21.64058283864004
1963	16.21488417939872
1964	21.672661870503596
1965	22.81964436917866
1966	24.844036697247702
1967	22.718052738336713
1968	23.26748196926936
1969	26.795895096921324
1970	26.2936695560809
1971	24.658519051042415
1972	22.58919469928644
1973	23.791469194312796
1974	25.22603978300181
1975	24.618480630555087
1976	24.268786560671966
1977	24.176128496261427
1978	23.97644803505409
1979	25.029603315571343
1980	23.16510555011883
1981	25.09136913129041
1982	24.40061871616396
1983	25.417216952815462
1984	27.03441987690905
1985	30.72649124646189
1986	34.41702951136914
1987	29.225630658345786
1988	24.68738506803972
1989	31.05590062111801
1990	30.740187209942576
1991	31.560640024735253
1992	33.1049378118716
1993	32.043487590301126
1994	36.357065413805564
1995	34.00737715715979
1996	34.165923282783226
1997	35.750354609929076
1998	38.15149802148105
1999	40.60201425823243
2000	37.229179089644205
2001	41.96746453415129
2002	37.09702538545399
2003	35.59773231451812
2004	35.565964844504535
2005	37.55492853508488
2006	37.67535070140281
2007	40.08739217237352
2008	43.19365798414497
2009	43.705925897066265
2010	42.59929158188259
2011	43.277502721303414
2012	41.74183103710312
2013	42.70774647887324
2014	46.69011103513399