Year	billion cubic meters
1975	1.2
1976	1.254
1977	1.308
1978	1.362
1979	1.416
1980	1.47
1981	1.799
1982	2.128
1983	2.457
1984	2.786
1985	3.115
1986	3.444
1987	3.773
1988	4.102
1989	4.431
1990	4.76
1991	4.72
1992	4.68
1993	4.64
1994	4.6
1995	4.55428
1996	4.50856
1997	4.46284
1998	4.39912
1999	4.3534
2000	4.308
2001	4.4237
2002	4.5394
2003	4.6551
2004	4.7708
2005	4.8865
2006	5.0055714286
2007	5.1246428571
2008	5.2437142857
2009	5.3627857143
2010	5.4818571429
2011	5.6009285714
2012	5.72
2013	5.72
2014	5.72
2015	5.72
2016	5.72
2017	5.72
2018	5.72
2019	5.72
2020	5.72