Year	metric tons
1961	130
1962	130
1963	140
1964	140
1965	150
1966	150
1967	160
1968	160
1969	160
1970	160
1971	170
1972	170
1973	180
1974	180
1975	190
1976	200
1977	200
1978	200
1979	220
1980	230
1981	235
1982	240
1983	250
1984	230
1985	200
1986	180
1987	180
1988	160
1989	160
1990	150
1991	159.4
1992	161.78
1993	160
1994	174.37
1995	170
1996	172.59
1997	173.76
1998	168.15
1999	174.24
2000	175.21
2001	173.8
2002	176.14
2003	180
2004	182.02
2005	190
2006	200
2007	210
2008	190.21
2009	184.23
2010	170
2011	140
2012	200
2013	200
2014	193.88
2015	188.94
2016	188.27
2017	189.57
2018	190.47
2019	191.21
2020	190.98
2021	191.3
2022	191.62