Year	billion cubic meters
1961	3
1962	3
1963	3
1964	3
1965	3
1966	3
1967	3
1968	3
1969	3
1970	3
1971	3
1972	3
1973	3
1974	3
1975	3
1976	3
1977	3
1978	3
1979	3
1980	3
1981	3
1982	3
1983	3
1984	3
1985	3
1986	3
1987	3
1988	3
1989	3
1990	3
1991	3
1992	3
1993	3
1994	3
1995	3
1996	3
1997	3
1998	3
1999	3
2000	3
2001	3
2002	3
2003	3
2004	3
2005	3
2006	3
2007	3
2008	3
2009	3
2010	3
2011	3
2012	3
2013	3
2014	3
2015	3
2016	3
2017	3
2018	3
2019	3
2020	3