Year billion cubic meters 1961 24370.807 1962 24478.332000000002 1963 24478.332000000002 1964 24478.332 1965 24478.331999999995 1966 24478.332000000002 1967 24478.332 1968 24478.331999999995 1969 24478.332 1970 24478.332000000002 1971 24478.332 1972 24478.332000000002 1973 24478.332000000002 1974 24478.332 1975 24478.332 1976 24478.332 1977 24478.332 1978 24478.332000000002 1979 24478.332000000002 1980 24478.332 1981 24478.332000000002 1982 24478.332000000002 1983 24478.332000000002 1984 24478.332000000002 1985 24478.332 1986 24478.332 1987 24478.332000000002 1988 24478.332000000002 1989 24478.332000000002 1990 24478.332000000002 1991 24478.332 1992 29189.541 1993 29189.541 1994 29175.541 1995 29175.541 1996 29174.641000000003 1997 29175.541 1998 29175.541 1999 29175.541 2000 29175.541 2001 29175.541 2002 29175.541 2003 29175.540999999994 2004 29172.540999999994 2005 29172.541 2006 29180.948 2007 29180.948 2008 29180.947999999993 2009 29180.947999999997 2010 29180.948 2011 29180.948 2012 29180.948 2013 29180.947999999997 2014 29180.947999999993 2015 29180.947999999993 2016 29180.948 2017 29180.948 2018 29180.947999999997 2019 29180.947999999997 2020 29180.948