Year billion cubic meters 1988 0.5 1989 0.5284470588 1990 0.5568941176 1991 0.5853411765 1992 0.6137882353 1993 0.6422352941 1994 0.6706823529 1995 0.6991294118 1996 0.7275764706 1997 0.7560235294 1998 0.7844705882 1999 0.8129176471 2000 0.8413647059 2001 0.8698117647 2002 0.8982588235 2003 0.9267058824 2004 0.9551529412 2005 0.9836 2006 1.0422555556 2007 1.1009111111 2008 1.1595666667 2009 1.2182222222 2010 1.2768777778 2011 1.3355333333 2012 1.3941888889 2013 1.4528444444 2014 1.5115 2015 1.7215 2016 1.7472 2017 1.581289 2018 2.431511 2019 2.5833078 2020 2.5833078