Year % of total fuel combustion 1960 32.30738849550033 1961 32.69523883334625 1962 34.156287616380475 1963 34.19066755972316 1964 34.34646147615672 1965 34.81899497101616 1966 34.679040989945854 1967 34.91099350493145 1968 35.00993455697434 1969 35.20859047148852 1970 37.68728346680297 1971 27.147069664577955 1972 27.561305196472073 1973 29.172098072277365 1974 29.259738834631843 1975 28.92302855819186 1976 29.05118944026574 1977 29.647576448576274 1978 30.40652687991732 1979 30.88757435756064 1980 32.11456695696669 1981 32.09168277218323 1982 31.750722046944727 1983 31.644849542648437 1984 31.95417066270983 1985 33.015022708745775 1986 33.11889492999472 1987 33.684956201039704 1988 34.696825591622186 1989 36.33079974294768 1990 38.01540946353282 1991 39.09532339653676 1992 40.37672396518526 1993 40.99411958220248 1994 42.278467043967645 1995 41.55645704098526 1996 44.46666331889007 1997 44.53961230139328 1998 46.00537823231238 1999 46.874581878778294 2000 48.31257284081235 2001 48.645782763114205 2002 49.90667462476212 2003 50.97570236435645 2004 49.278739833883996 2005 49.637520941117785 2006 50.553092323290414 2007 51.070526046172986 2008 50.4313080361917 2009 50.49146175028091 2010 51.55546171171171 2011 52.551434455816235 2012 52.7814634805904 2013 53.155280315681715 2014 52.44682801255924