Year	metric tons
1960	60
1961	80
1962	100
1963	120
1964	150
1965	180
1966	220
1967	250
1968	310
1969	350
1970	400
1971	470
1972	530
1973	600
1974	680
1975	770
1976	860
1977	970
1978	1090
1979	1220
1980	1370
1981	1540
1982	1740
1983	1970
1984	2226
1985	2700
1986	3075
1987	3300
1988	4100
1989	4354
1990	5782
1991	7835
1992	9085
1993	12438
1994	15998
1995	21607
1996	33201
1997	45450
1998	56700
1999	63000
2000	79031
2001	67244
2002	61165
2003	79943
2004	94450
2005	119567
2006	129333
2007	140743
2008	152896
2009	159639
2010	167721
2011	188890
2012	212805
2013	233863.6
2014	235133
2015	240334
2016	253395
2017	276502
2018	314537
2019	373356
2020	421411
2021	471686
2022	514823