Year	billion cubic meters
1970	10.113
1971	10.7968
1972	11.4806
1973	12.1644
1974	12.8482
1975	13.532
1976	13.8518
1977	14.1716
1978	14.4914
1979	14.8112
1980	15.131
1981	15.3874
1982	15.6438
1983	15.9002
1984	16.1566
1985	16.413
1986	16.1638
1987	15.9146
1988	15.6654
1989	15.4162
1990	15.167
1991	14.2735
1992	13.38
1993	13.2626
1994	13.1452
1995	13.0278
1996	12.9104
1997	12.793
1998	12.5782
1999	12.3634
2000	12.1486
2001	11.9338
2002	11.719
2003	11.7792
2004	11.8382
2005	11.8978
2006	11.9574
2007	12.02
2008	11.36
2009	11.51
2010	10.87
2011	11.91
2012	11.47
2013	11.24
2014	10.631
2015	10.448
2016	10.289
2017	10.08
2018	9.598
2019	8.983979
2020	8.667