Year billion cubic meters 1993 18.5502 1994 21.1102 1995 19.8502 1996 22.1602 1997 21.9282 1998 21.8222 1999 21.7162 2000 21.65924 2001 21.534 2002 20.8338 2003 20.1336 2004 19.4334 2005 18.7332 2006 17.55665 2007 16.3801 2008 15.20355 2009 14.027 2010 13.175 2011 13.215 2012 15.868 2013 19.148 2014 18.463 2015 9.22 2016 10.623 2017 12.05864137 2018 12.33 2019 10.53 2020 8.64