Year	billion cubic meters
1961	0.75
1962	0.75
1963	0.75
1964	0.75
1965	0.75
1966	0.75
1967	0.75
1968	0.75
1969	0.75
1970	0.75
1971	0.75
1972	0.75
1973	0.75
1974	0.75
1975	0.75
1976	0.75
1977	0.75
1978	0.75
1979	0.75
1980	0.75
1981	0.75
1982	0.75
1983	0.75
1984	0.75
1985	0.75
1986	0.75
1987	0.75
1988	0.75
1989	0.75
1990	0.75
1991	0.75
1992	0.75
1993	0.75
1994	0.75
1995	0.75
1996	0.75
1997	0.75
1998	0.75
1999	0.75
2000	0.75
2001	0.75
2002	0.75
2003	0.75
2004	0.75
2005	0.75
2006	0.75
2007	0.75
2008	0.75
2009	0.75
2010	0.75
2011	0.75
2012	0.75
2013	0.75
2014	0.75
2015	0.75
2016	0.75
2017	0.75
2018	0.75
2019	0.75
2020	0.75