Year billion cubic meters 2007 0.0429 2008 0.0429 2009 0.0429 2010 0.0429 2011 0.0429 2012 0.0429 2013 0.0429 2014 0.0429 2015 0.0429 2016 0.0429 2017 0.0429 2018 0.0429 2019 0.0429 2020 0.0429