Year	billion cubic meters
1961	2.18
1962	2.18
1963	2.18
1964	2.18
1965	2.18
1966	2.18
1967	2.18
1968	2.18
1969	2.18
1970	2.18
1971	2.18
1972	2.18
1973	2.18
1974	2.18
1975	2.18
1976	2.18
1977	2.18
1978	2.18
1979	2.18
1980	2.18
1981	2.18
1982	2.18
1983	2.18
1984	2.18
1985	2.18
1986	2.18
1987	2.18
1988	2.18
1989	2.18
1990	2.18
1991	2.18
1992	2.18
1993	2.18
1994	2.18
1995	2.18
1996	2.18
1997	2.18
1998	2.18
1999	2.18
2000	2.18
2001	2.18
2002	2.18
2003	2.18
2004	2.18
2005	2.18
2006	2.18
2007	2.18
2008	2.18
2009	2.18
2010	2.18
2011	2.18
2012	2.18
2013	2.18
2014	2.18
2015	2.18
2016	2.18
2017	2.18
2018	2.18
2019	2.18
2020	2.18