Year	metric tons
1960	817
1961	817
1962	917
1963	917
1964	917
1965	917
1966	875
1967	875
1968	1235
1969	1235
1970	1661
1971	2469
1972	2878
1973	3286
1974	4046
1975	4755
1976	4863
1977	5620
1978	6026
1979	6485
1980	6951
1981	7459
1982	7974
1983	8493
1984	8999
1985	9515
1986	9970
1987	10378
1988	10913
1989	10751
1990	11251
1991	11551
1992	12590
1993	12757
1994	13537
1995	13109
1996	12696
1997	12576
1998	12317
1999	11818
2000	12003
2001	11425
2002	11178
2003	11053
2004	10987
2005	10738
2006	10464
2007	14401
2008	22714
2009	44745
2010	63447
2011	38180
2012	36296
2013	43732
2014	9256
2015	12674
2016	16407