Year	billion cubic meters
1961	136.6
1962	136.6
1963	136.6
1964	136.6
1965	136.6
1966	136.6
1967	136.6
1968	136.6
1969	136.6
1970	136.6
1971	136.6
1972	136.6
1973	136.6
1974	136.6
1975	136.6
1976	136.6
1977	136.6
1978	136.6
1979	136.6
1980	136.6
1981	136.6
1982	136.6
1983	136.6
1984	136.6
1985	136.6
1986	136.6
1987	136.6
1988	136.6
1989	136.6
1990	136.6
1991	136.6
1992	136.6
1993	136.6
1994	136.6
1995	136.6
1996	136.6
1997	136.6
1998	136.6
1999	136.6
2000	136.6
2001	136.6
2002	136.6
2003	136.6
2004	136.6
2005	136.6
2006	136.6
2007	136.6
2008	136.6
2009	136.6
2010	136.6
2011	136.6
2012	136.6
2013	136.6
2014	136.6
2015	136.6
2016	136.6
2017	136.6
2018	136.6
2019	136.6
2020	136.6