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	21
1985	60
1986	213
1987	229
1988	170
1989	168
1990	100
1991	253
1992	306
1993	351
1994	117
1995	386
1996	1128
1997	450
1998	862
1999	1000
2000	1197
2001	1025
2002	806
2003	866
2004	866
2005	866
2006	866
2007	1290
2008	1290
2009	1340
2010	1700
2011	3394
2012	3720
2013	3720
2014	3750
2015	4000
2016	4392
2017	4500
2018	4700
2019	5020
2020	5420
2021	5720
2022	6200