Year	billion cubic meters
1987	1.36
1988	1.6310175439
1989	1.9020350877
1990	2.1730526316
1991	2.4440701754
1992	2.7150877193
1993	2.9861052632
1994	3.257122807
1995	3.5281403509
1996	3.7991578947
1997	4.0558421053
1998	4.3125263158
1999	4.5692105263
2000	4.8258947368
2001	5.0825789474
2002	5.1032631579
2003	5.1239473684
2004	5.1446315789
2005	5.1653157895
2006	5.186
2007	5.186
2008	5.186
2009	5.186
2010	5.186
2011	5.186
2012	5.186
2013	5.186
2014	5.186
2015	5.186
2016	5.186
2017	5.186
2018	5.186
2019	5.186
2020	5.186