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	4
1977	11
1978	25
1979	53
1980	106
1981	240
1982	464
1983	934
1984	1610
1985	3000
1986	2200
1987	2500
1988	4600
1989	5538
1990	6400
1991	6700
1992	8550
1993	7900
1994	8200
1995	9511
1996	9600
1997	11800
1998	14100
1999	15000
2000	14430
2001	17500
2002	18250
2003	26300
2004	37515
2005	44000
2006	41010
2007	35260
2008	40000
2009	50000
2010	60000
2011	72000
2012	74000
2013	90000
2014	120055
2015	145000
2016	172500
2017	207500
2018	254050
2019	307408
2020	400400
2021	348350
2022	330600