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 1690 1993 1201 1994 1038 1995 516 1996 419 1997 364 1998 211 1999 216 2000 140 2001 95 2002 80 2003 130 2004 350 2005 500 2006 600 2007 900 2008 1000 2009 1000 2010 1000 2011 517 2012 366.1 2013 325 2014 305 2015 561 2016 640 2017 695 2018 478 2019 531.4 2020 533 2021 507 2022 466