Year	metric tons
1960	600
1961	600
1962	600
1963	700
1964	700
1965	700
1966	800
1967	800
1968	800
1969	800
1970	1000
1971	1000
1972	1000
1973	1000
1974	1000
1975	1218
1976	1684
1977	1695
1978	1790
1979	1777
1980	1935
1981	1900
1982	1930
1983	1177
1984	1115
1985	995
1986	901
1987	924
1988	800
1989	713
1990	623
1991	453
1992	300
1993	250
1994	357
1995	339
1996	687
1997	418
1998	967
1999	934
2000	971
2001	1040
2002	950
2003	874
2004	1112
2005	1517
2006	1180
2007	1276
2008	1343
2009	2065
2010	21755
2011	31072
2012	21888
2013	17718
2014	66143.2
2015	100400.02
2016	65769.93
2017	84960.17
2018	1046.87
2019	654.5
2020	650.04
2021	676.03
2022	674