Year billion cubic meters 1992 31.5995 1993 32.2743214286 1994 32.9491428571 1995 33.6239642857 1996 34.2987857143 1997 34.9736071429 1998 35.6484285714 1999 36.32325 2000 42 2001 40.9391666667 2002 39.8783333333 2003 38.8175 2004 39.5380833333 2005 40.2586666667 2006 40.97925 2007 41.469625 2008 41.96 2009 45.13 2010 46.96 2011 48.735 2012 50.51 2013 51.24 2014 51.97 2015 53.71 2016 59.61 2017 58.788985 2018 61.09358 2019 61.53358 2020 61.53358