Year	billion cubic meters
1985	0.008
1986	0.0087333333
1987	0.0094666667
1988	0.0102
1989	0.0109333333
1990	0.0116666667
1991	0.0124
1992	0.0131333333
1993	0.0138666667
1994	0.0145
1995	0.0153333333
1996	0.0160666667
1997	0.0168
1998	0.0174333333
1999	0.0182666667
2000	0.019
2001	0.019
2002	0.019
2003	0.019
2004	0.019
2005	0.019
2006	0.019
2007	0.019
2008	0.019
2009	0.019
2010	0.019
2011	0.019
2012	0.019
2013	0.019
2014	0.019
2015	0.019
2016	0.019
2017	0.019
2018	0.019
2019	0.019
2020	0.019