Year billion cubic meters 2006 3.87265 2007 3.9578 2008 4.691 2009 4.634 2010 4.419 2011 4.75 2012 4.403 2013 4.709 2014 3.935 2015 4.689 2016 4.707 2017 5.377 2018 5.5575 2019 5.6186 2020 5.3245