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	10
1985	30
1986	41
1987	43
1988	45
1989	100
1990	234
1991	203
1992	200
1993	200
1994	200
1995	1000
1996	1000
1997	1000
1998	1000
1999	1000
2000	1000
2001	1000
2002	1600
2003	1600
2004	1600
2005	1600
2006	1600
2007	1950
2008	1800
2009	2000
2010	2000
2011	2000
2012	7500
2013	6500
2014	6000
2015	7000
2016	6000
2017	9000
2018	10000
2019	9000
2020	9000
2021	9000
2022	9000