Year billion cubic meters 1992 16.12 1993 16.569525 1994 17.00505 1995 17.472575 1996 17.9091 1997 18.368625 1998 18.81315 1999 19.237675 2000 19.6742 2001 19.9834625 2002 20.346725 2003 20.5959875 2004 20.88325 2005 21.4756875 2006 22.64 2007 22.4670833333 2008 22.2941666667 2009 22.12125 2010 21.9483333333 2011 21.7754166667 2012 21.6025 2013 21.46175 2014 21.473 2015 22.773 2016 22.31 2017 22.943 2018 23.38 2019 23.38 2020 23.38