Year	billion cubic meters
1975	0.19
1976	0.2580225
1977	0.326045
1978	0.3940675
1979	0.46209
1980	0.5301125
1981	0.598135
1982	0.6661575
1983	0.73418
1984	0.8022025
1985	0.870225
1986	0.9382475
1987	1.00627
1988	1.0742925
1989	1.142315
1990	1.2031375
1991	1.27116
1992	1.3391825
1993	1.407205
1994	1.4752275
1995	1.54325
1996	1.6112725
1997	1.679295
1998	1.7473175
1999	1.81534
2000	1.8833625
2001	1.969417
2002	2.0294715
2003	2.115126
2004	2.2007805
2005	2.2651016667
2006	2.0777348333
2007	1.890368
2008	1.7067345
2009	1.513101
2010	1.3194675
2011	1.125834
2012	0.9602005
2013	0.794567
2014	0.6510335
2015	0.5075
2016	0.5098
2017	0.4993
2018	0.4883
2019	0.493
2020	0.4987