Year	billion cubic meters
1961	4.8
1962	4.8
1963	4.8
1964	4.8
1965	4.8
1966	4.8
1967	4.8
1968	4.8
1969	4.8
1970	4.8
1971	4.8
1972	4.8
1973	4.8
1974	4.8
1975	4.8
1976	4.8
1977	4.8
1978	4.8
1979	4.8
1980	4.8
1981	4.8
1982	4.8
1983	4.8
1984	4.8
1985	4.8
1986	4.8
1987	4.8
1988	4.8
1989	4.8
1990	4.8
1991	4.8
1992	4.8
1993	4.8
1994	4.8
1995	4.8
1996	4.8
1997	4.8
1998	4.8
1999	4.8
2000	4.8
2001	4.8
2002	4.8
2003	4.8
2004	4.8
2005	4.8
2006	4.8
2007	4.8
2008	4.8
2009	4.8
2010	4.8
2011	4.8
2012	4.8
2013	4.8
2014	4.8
2015	4.8
2016	4.8
2017	4.8
2018	4.8
2019	4.8
2020	4.8