Year billion cubic meters 1975 153.368 1976 153.5075 1977 153.647 1978 153.7865 1979 153.926 1980 154.0655 1981 154.205 1982 154.3445 1983 154.484 1984 154.6235 1985 154.763 1986 154.9025 1987 155.042 1988 155.1815 1989 155.321 1990 155.4605 1991 155.6 1992 157.4844444444 1993 159.3688888889 1994 161.2533333333 1995 163.1377777778 1996 165.0222222222 1997 166.9066666667 1998 168.7911111111 1999 170.6755555556 2000 172.56 2001 173.83575 2002 175.1115 2003 176.38725 2004 177.663 2005 178.93875 2006 180.4425 2007 181.94625 2008 183.5 2009 183.09 2010 185.28 2011 179.48 2012 187.88 2013 183.5 2014 194.87 2015 196.9 2016 199.77 2017 199.97 2018 192.74 2019 177.11 2020 189.59