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	0
1985	0
1986	0
1987	0
1988	1
1989	33
1990	36
1991	36
1992	22
1993	28
1994	33
1995	55
1996	38
1997	24
1998	14
1999	15
2000	15
2001	15
2002	15
2003	15
2004	25
2005	25
2006	25
2007	25
2008	25
2009	25
2010	25
2011	25
2012	38
2013	45.3
2014	85.5
2015	90.5
2016	95
2017	126
2018	165
2019	430
2020	534
2021	740
2022	1070