Year billion cubic meters 2000 4.865 2001 4.9822 2002 5.0994 2003 5.2166 2004 5.3338 2005 5.451 2006 5.7882 2007 6.1254 2008 6.4626 2009 6.7998 2010 7.137 2011 7.137 2012 7.137 2013 7.137 2014 7.137 2015 7.137 2016 7.137 2017 7.137 2018 7.137 2019 7.137 2020 7.137