Year	metric tons
1960	100
1961	100
1962	100
1963	100
1964	100
1965	100
1966	100
1967	100
1968	100
1969	100
1970	100
1971	100
1972	100
1973	100
1974	91
1975	131
1976	95
1977	184
1978	200
1979	164
1980	257
1981	326
1982	444
1983	327
1984	395
1985	518
1986	567
1987	500
1988	593
1989	550
1990	688
1991	690
1992	575
1993	599
1994	613
1995	482
1996	480
1997	491
1998	575
1999	554
2000	856
2001	905
2002	668
2003	616
2004	692
2005	440
2006	580
2007	488
2008	491
2009	602.5
2010	296.77
2011	231.49
2012	212.48000000000002
2013	218.68
2014	197.41
2015	181.62
2016	179.8
2017	252.42
2018	197.85
2019	195.2
2020	155.14
2021	130.69
2022	459.5