Year	metric tons
1961	13000
1962	13000
1963	13000
1964	13000
1965	17000
1966	19000
1967	22000
1968	11000
1969	7000
1970	924
1971	910
1972	575
1973	714
1974	2200
1975	4000
1976	5000
1977	1500
1978	1000
1979	6000
1980	8500
1981	3000
1982	4400
1983	2700
1984	2525
1985	1323
1986	12138
1987	21182
1988	16507
1989	9714
1990	11418
1991	8258
1992	10265
1993	11888
1994	8163
1995	8166
1996	10190
1997	4900
1998	4883
1999	36439
2000	24341
2001	19549
2002	5067
2003	12154
2004	10000
2005	3648
2006	6378
2007	4425
2008	8039
2009	7383
2010	7047
2011	5569
2012	6001
2013	5785
2014	1065
2015	8677
2016	5642
2017	4
2018	719.4
2019	640
2020	432
2021	449
2022	221.6