Year	billion cubic meters
1961	95
1962	95
1963	95
1964	95
1965	95
1966	95
1967	95
1968	95
1969	95
1970	95
1971	95
1972	95
1973	95
1974	95
1975	95
1976	95
1977	95
1978	95
1979	95
1980	95
1981	95
1982	95
1983	95
1984	95
1985	95
1986	95
1987	95
1988	95
1989	95
1990	95
1991	95
1992	95
1993	95
1994	81
1995	81
1996	81
1997	81
1998	81
1999	81
2000	81
2001	81
2002	81
2003	81
2004	78
2005	78
2006	78
2007	78
2008	78
2009	78
2010	78
2011	78
2012	78
2013	78
2014	78
2015	78
2016	78
2017	78
2018	78
2019	78
2020	78