Year	metric tons
1960	30000
1961	30000
1962	35000
1963	35000
1964	35000
1965	38000
1966	38000
1967	40000
1968	40000
1969	40000
1970	40000
1971	43000
1972	43000
1973	43000
1974	67800
1975	67800
1976	64600
1977	64600
1978	64600
1979	64600
1980	64600
1981	67760
1982	69755
1983	72716
1984	72716
1985	72260
1986	79321
1987	85243
1988	89500
1989	91160
1990	95129
1991	92336
1992	95046
1993	99600
1994	108600
1995	105884
1996	107000
1997	114358
1998	114739
1999	117607
2000	105456
2001	112561
2002	97574
2003	95150
2004	90000
2005	86735
2006	100403
2007	96453
2008	74075
2009	77705
2010	70590
2011	75147
2012	72728
2013	73203
2014	73018
2015	74056
2016	73287
2017	75287
2018	75615
2019	72117
2020	71388
2021	67944
2022	65510