Year metric tons 1960 0 1961 0 1962 0 1963 0 1964 0 1965 0 1966 0 1967 0 1968 0 1969 0 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 0 1991 0 1992 642 1993 223 1994 163 1995 207 1996 185 1997 168 1998 162 1999 71 2000 58 2001 144 2002 94 2003 12 2004 20 2005 20 2006 20 2007 107 2008 92 2009 133 2010 352 2011 394.5 2012 297 2013 300 2014 577.93 2015 1068.4 2016 1930.7 2017 2100 2018 2558.7 2019 4300 2020 5100 2021 10300 2022 20698.3