Year billion cubic meters 2001 2.427397619 2002 2.6067380952 2003 2.7860785714 2004 2.9654190476 2005 3.1447595238 2006 3.3241 2007 3.3241 2008 3.3241 2009 3.3241 2010 3.3241 2011 3.3241 2012 3.3241 2013 3.3241 2014 3.3241 2015 3.3241 2016 3.3241 2017 3.3241 2018 3.3241 2019 3.3241 2020 3.3241