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	5
1976	10
1977	20
1978	40
1979	25
1980	40
1981	70
1982	120
1983	200
1984	300
1985	300
1986	375
1987	200
1988	100
1989	100
1990	80
1991	80
1992	130
1993	180
1994	200
1995	300
1996	350
1997	300
1998	400
1999	300
2000	400
2001	300
2002	790
2003	795
2004	795
2005	813
2006	813
2007	818
2008	975
2009	1080
2010	1180
2011	1280
2012	1280
2013	1180
2014	1135
2015	1035
2016	1035
2017	1035
2018	940
2019	940
2020	933
2021	936
2022	938