Year	metric tons
1960	3000
1961	3000
1962	3000
1963	3200
1964	3400
1965	3500
1966	3500
1967	3500
1968	3800
1969	3800
1970	3900
1971	3900
1972	4700
1973	4700
1974	4800
1975	5036
1976	5589
1977	7935
1978	9250
1979	20243
1980	20404
1981	23608
1982	24931
1983	24227
1984	25633
1985	26113
1986	26440.4
1987	27774.5
1988	29120
1989	29475.3
1990	33175.77
1991	29518.38
1992	25188.2
1993	28814
1994	30116
1995	30307
1996	26622
1997	29721
1998	30667.61
1999	39206
2000	42366
2001	45106
2002	40320
2003	37237.8
2004	49632.66
2005	47390
2006	48733
2007	47247
2008	46595
2009	46387
2010	41943
2011	46907
2012	46851
2013	42639
2014	43312
2015	41266
2016	44826
2017	47500
2018	42729.41
2019	41698.87
2020	37597.12
2021	33009.48
2022	32626.2