Year billion cubic meters 1992 16.202 1993 16.338 1994 14.633 1995 13.97 1996 13.457 1997 12.518 1998 10.235 1999 11.968 2000 10.99 2001 9.923 2002 9.919 2003 10.518 2004 11.175 2005 11.8 2006 12.144 2007 12.085 2008 11.53 2009 11.14 2010 10.97 2011 11.296 2012 11.975 2013 11.994 2014 11.592 2015 11.689 2016 11.878 2017 12.12 2018 12.167 2019 12.59 2020 12.59