Year	billion cubic meters
1987	28.256
1988	28.6382538462
1989	29.0213846154
1990	29.4027615385
1991	29.7850153846
1992	30.1672692308
1993	30.5495230769
1994	30.9317769231
1995	31.3140307692
1996	31.6962846154
1997	32.0785384615
1998	32.4607923077
1999	32.8430461538
2000	33.231
2001	33.231
2002	33.231
2003	33.231
2004	33.231
2005	33.231
2006	33.231
2007	33.231
2008	33.231
2009	33.231
2010	33.231
2011	33.231
2012	33.231
2013	33.231
2014	33.231
2015	33.231
2016	33.231
2017	33.231
2018	33.231
2019	33.231
2020	33.231