Year billion cubic meters 1993 2.8 1994 2.8 1995 2.8 1996 2.8 1997 2.8 1998 2.8 1999 2.8 2000 2.8 2001 2.8 2002 2.8 2003 2.8 2004 2.8 2005 2.8 2006 2.8 2007 2.8 2008 2.8 2009 2.8 2010 2.8 2011 2.8 2012 2.8 2013 2.8 2014 2.8 2015 2.8 2016 2.8 2017 2.8 2018 2.8 2019 2.8 2020 2.8