Year billion cubic meters 1991 8.5984 1992 10.0701619048 1993 11.5419238095 1994 13.0136857143 1995 12.8521142857 1996 12.2795428571 1997 11.7069714286 1998 11.1344 1999 10.9010335338 2000 10.6646670677 2001 10.4313006015 2002 10.1979341353 2003 9.9645676692 2004 9.731201203 2005 9.4978347368 2006 9.0587968421 2007 9.146 2008 9.0792888889 2009 9.0125777778 2010 8.9458666667 2011 8.8791555556 2012 8.8124444444 2013 8.7457333333 2014 8.6790222222 2015 8.6123111111 2016 8.5456 2017 6.16147 2018 6.12953 2019 6.12953 2020 6.12953