Year	billion cubic meters
2001	0.02155
2002	0.0228
2003	0.02405
2004	0.0253
2005	0.0253
2006	0.0253
2007	0.0253
2008	0.0253
2009	0.0253
2010	0.0253
2011	0.0253
2012	0.0253
2013	0.0253
2014	0.0253
2015	0.0253
2016	0.0253
2017	0.0253
2018	0.0253
2019	0.0253
2020	0.0253