Year	billion cubic meters
1975	3.34
1976	3.8637777778
1977	4.3875555556
1978	4.9113333333
1979	5.4351111111
1980	5.9588888889
1981	6.4826666667
1982	7.0064444444
1983	7.5302222222
1984	8.054
1985	8.5777777778
1986	9.1015555556
1987	9.6253333333
1988	10.1491111111
1989	10.6728888889
1990	11.1966666667
1991	11.7204444444
1992	12.2442222222
1993	12.768
1994	13.449
1995	13.492
1996	13.964
1997	14.427
1998	14.917
1999	14.698
2000	15.072
2001	15.554
2002	16.359
2003	14.445
2004	14.1097
2005	14.1444
2006	14.1444
2007	14.1444
2008	14.1444
2009	14.0994
2010	14.0544
2011	14.0094
2012	13.9644
2013	13.9644
2014	13.9644
2015	13.9644
2016	13.9644
2017	13.9644
2018	13.9644
2019	13.9644
2020	13.9644