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	81
1985	180
1986	689
1987	723
1988	759
1989	760
1990	700
1991	700
1992	730
1993	700
1994	650
1995	600
1996	600
1997	1000
1998	1833
1999	1993
2000	2076
2001	2744
2002	2965
2003	2965
2004	2965
2005	3015
2006	3020
2007	3020.5
2008	3025
2009	3025
2010	3025
2011	3030
2012	2929
2013	2921
2014	2921
2015	3007
2016	3226
2017	3580
2018	3880
2019	4290
2020	4690
2021	5195