Year billion cubic meters 1992 1.963 1993 1.85265 1994 1.7423 1995 1.63195 1996 1.5216 1997 1.4889545455 1998 1.4563090909 1999 1.4236636364 2000 1.3910181818 2001 0.874 2002 0.866 2003 0.864 2004 0.852 2005 0.852 2006 0.854 2007 0.854 2008 0.885 2009 0.865 2010 0.851 2011 0.847 2012 0.85 2013 0.839 2014 0.837 2015 0.84 2016 0.843 2017 0.84 2018 0.837 2019 0.839 2020 0.846