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	33727
1993	18243
1994	17265
1995	11409
1996	9321
1997	8784
1998	7573
1999	9131
2000	12296
2001	12792
2002	12850
2003	14567
2004	15008
2005	15026
2006	15026
2007	15026
2008	15026
2009	15026
2010	15026
2011	15026
2012	15026
2013	15030
2014	15050
2015	15050
2016	15075
2017	15080
2018	15120
2019	15140
2020	14755
2021	15202
2022	15272