Year billion cubic meters 1961 12667.300000000001 1962 12667.300000000001 1963 12667.300000000001 1964 12667.300000000001 1965 12667.300000000001 1966 12667.300000000001 1967 12667.300000000001 1968 12667.300000000001 1969 12667.300000000001 1970 12667.300000000001 1971 12667.300000000001 1972 12667.300000000001 1973 12667.300000000001 1974 12667.300000000001 1975 12667.300000000001 1976 12667.300000000001 1977 12667.300000000001 1978 12667.300000000001 1979 12667.300000000001 1980 12667.300000000001 1981 12667.300000000001 1982 12667.300000000001 1983 12667.300000000001 1984 12667.300000000001 1985 12667.300000000001 1986 12667.300000000001 1987 12667.300000000001 1988 12667.300000000001 1989 12667.300000000001 1990 12667.300000000001 1991 12667.300000000001 1992 12731.08 1993 12756.829999999998 1994 12756.829999999998 1995 12756.829999999998 1996 12756.829999999998 1997 12756.829999999998 1998 12756.829999999998 1999 12756.829999999998 2000 12756.829999999998 2001 12756.829999999998 2002 12756.829999999998 2003 12756.829999999998 2004 12756.829999999998 2005 12756.829999999998 2006 12756.829999999998 2007 12756.829999999998 2008 12756.829999999998 2009 12756.829999999998 2010 12756.829999999998 2011 12756.829999999998 2012 12756.829999999998 2013 12756.829999999998 2014 12756.829999999998 2015 12756.829999999998 2016 12756.829999999998 2017 12756.829999999998 2018 12756.829999999998 2019 12756.829999999998 2020 12756.829999999998