Year % of total fuel combustion 1960 42.2718222781096 1961 44.38752448395359 1962 43.936522974893414 1963 44.53919317809118 1964 45.551745917170436 1965 44.86996793729961 1966 45.986290406764326 1967 47.21141813508302 1968 48.93804443574435 1969 48.84400097347286 1970 47.721369539551354 1971 39.57025759494552 1972 41.03860543295559 1973 41.6918901993529 1974 42.74128660647007 1975 41.86992364924928 1976 42.75356462506494 1977 43.11470692403046 1978 44.54723563862667 1979 43.531747656281986 1980 43.69447574954565 1981 45.016675960314366 1982 45.37886226419035 1983 46.637646665831554 1984 47.106513551512165 1985 47.54991659505636 1986 47.64997824969352 1987 46.73858697742395 1988 46.43853250375456 1989 48.49242431879354 1990 54.12977995609333 1991 55.03347521503945 1992 58.85043396837973 1993 57.851983334565986 1994 56.87288717179677 1995 55.23008324175477 1996 55.09593575675841 1997 54.406455454073296 1998 55.67307951755214 1999 55.54381656720255 2000 55.959537572254334 2001 56.447536561124515 2002 55.490275526742295 2003 56.078827550893315 2004 54.74037967476286 2005 54.11246971005208 2006 53.84520884520885 2007 54.62085629734206 2008 53.70699716556438 2009 53.45959066255133 2010 53.82506169454347 2011 54.96655252625951 2012 54.0620628450234 2013 53.38370513761182 2014 52.399909376314845