Year	billion cubic meters
1987	5.59
1988	5.9525384615
1989	6.3155384615
1990	6.6753076923
1991	7.0380769231
1992	7.4008461538
1993	7.7636153846
1994	8.1263846154
1995	8.4891538462
1996	8.8519230769
1997	9.2153846154
1998	9.5774615385
1999	9.9404615385
2000	10.303
2001	10.5566
2002	10.8102
2003	11.0638
2004	11.3174
2005	11.571
2006	11.7512
2007	11.9314
2008	12.1116
2009	12.2918
2010	12.472
2011	12.472
2012	12.472
2013	12.472
2014	12.472
2015	12.472
2016	12.472
2017	12.472
2018	12.472
2019	12.472
2020	12.472