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 195 1993 164 1994 196 1995 208 1996 78 1997 130 1998 131 1999 135 2000 208 2001 128 2002 148 2003 162 2004 213 2005 271 2006 147 2007 177 2008 166 2009 222 2010 236 2011 268 2012 249 2013 334 2014 282 2015 350 2016 122 2017 87 2018 140 2019 399.5 2020 472.88 2021 514 2022 447