Year metric tons 1960 0 1961 0 1962 0 1963 0 1964 0 1965 0 1966 4 1967 10 1968 20 1969 106 1970 254 1971 282 1972 402 1973 428 1974 343 1975 345 1976 510 1977 638 1978 714 1979 788 1980 989 1981 1138 1982 1387 1983 1794 1984 2907 1985 2839 1986 4285 1987 5878 1988 6965 1989 7697 1990 16664 1991 34997 1992 36916 1993 37422 1994 46495 1995 62486 1996 75786 1997 68010 1998 72304 1999 70004 2000 90371 2001 130605 2002 173065 2003 162527 2004 139343 2005 172302.15 2006 212289.2 2007 241078.7 2008 263596.25 2009 268125.31 2010 314846.79999999993 2011 344257.7 2012 402600.65 2013 385174.67000000004 2014 445655.14 2015 499395.14999999997 2016 455718.15 2017 483267.49000000005 2018 490083.18 2019 475835.73000000004 2020 516465.68999999994 2021 599142.49 2022 647405.2000000001