Year	billion cubic meters
1961	55
1962	55
1963	55
1964	55
1965	55
1966	55
1967	55
1968	55
1969	55
1970	55
1971	55
1972	55
1973	55
1974	55
1975	55
1976	55
1977	55
1978	55
1979	55
1980	55
1981	55
1982	55
1983	55
1984	55
1985	55
1986	55
1987	55
1988	55
1989	55
1990	55
1991	55
1992	55
1993	55
1994	55
1995	55
1996	55
1997	55
1998	55
1999	55
2000	55
2001	55
2002	55
2003	55
2004	55
2005	55
2006	55
2007	55
2008	55
2009	55
2010	55
2011	55
2012	55
2013	55
2014	55
2015	55
2016	55
2017	55
2018	55
2019	55
2020	55