Year billion cubic meters 1991 0.9799 1992 1.056075 1993 1.13225 1994 1.208425 1995 1.2846 1996 1.2964142857 1997 1.3082285714 1998 1.3200428571 1999 1.3318571429 2000 1.3436714286 2001 1.3554857143 2002 1.3673 2003 1.3791142857 2004 1.3909285714 2005 1.4027428571 2006 1.4145571429 2007 1.4263714286 2008 1.4381857143 2009 1.45 2010 1.45 2011 1.45 2012 1.45 2013 1.45 2014 1.45 2015 1.45 2016 1.45 2017 1.45 2018 1.45 2019 1.45 2020 1.45