Year	billion cubic meters
1987	0.74
1988	0.7275384615
1989	0.7150769231
1990	0.7026153846
1991	0.6901538462
1992	0.6776923077
1993	0.6652307692
1994	0.6527692308
1995	0.6403076923
1996	0.6278461538
1997	0.6153846154
1998	0.6029230769
1999	0.5904615385
2000	0.578
2001	0.557
2002	0.56125
2003	0.5655
2004	0.56975
2005	0.574
2006	0.5983076923
2007	0.6226153846
2008	0.6469230769
2009	0.6712307692
2010	0.6955384615
2011	0.7198461538
2012	0.7441538462
2013	0.7684615385
2014	0.7927692308
2015	0.8170769231
2016	0.8413846154
2017	0.8656923077
2018	0.89
2019	0.89
2020	0.89