Year	billion cubic meters
1961	1952.03
1962	1999.18
1963	1999.18
1964	1999.18
1965	1999.18
1966	1999.18
1967	1999.18
1968	1999.18
1969	1999.18
1970	1999.18
1971	1999.18
1972	1999.18
1973	1999.18
1974	1999.18
1975	1999.18
1976	1999.18
1977	1999.18
1978	1999.18
1979	1999.18
1980	1999.18
1981	1999.18
1982	1999.18
1983	1999.18
1984	1999.18
1985	1999.18
1986	1999.18
1987	1999.18
1988	1999.18
1989	1999.18
1990	1999.18
1991	1999.18
1992	1999.18
1993	1999.18
1994	1985.18
1995	1985.18
1996	1985.18
1997	1985.18
1998	1985.18
1999	1985.18
2000	1985.18
2001	1985.18
2002	1985.18
2003	1985.18
2004	1982.18
2005	1982.18
2006	1982.18
2007	1982.18
2008	1982.18
2009	1982.18
2010	1982.18
2011	1982.18
2012	1982.18
2013	1982.18
2014	1982.18
2015	1982.18
2016	1982.18
2017	1982.18
2018	1982.18
2019	1982.18
2020	1982.18