Year metric tons 1961 1537830 1962 3511979 1963 3856071 1964 3403305 1965 3486365 1966 2179840 1967 3523200 1968 6352730 1969 4089600 1970 4251560 1971 5352461 1972 5167140 1973 3228970 1974 4809380 1975 3728620 1976 5713380 1977 2888140 1978 4744560 1979 4103160 1980 4514720 1981 2130300 1982 4916509 1983 3581070 1984 3759130 1985 5312160 1986 7824550 1987 4336810 1988 7958960 1989 7428590 1990 6275864 1991 8664685 1992 2950232.19 1993 2817864.04 1994 9638630 1995 1783230 1996 10103303.7 1997 4097670.63 1998 6629516.41 1999 3843292.32 2000 1996648.9 2001 4603349.74 2002 5287814.6 2003 7969118.32 2004 8598634.63 2005 4279354.31 2006 9236077.13 2007 2505021.89 2008 5330290.42 2009 10443719.48 2010 7834479.24 2011 8689334 2012 5311218.76 2013 9874542.88 2014 6936819.24 2015 11687921.96 2016 3560828.31 2017 9787464.69 2018 10389766.77 2019 5316232.56 2020 3325551.12 2021 10452190.15 2022 3509673.38