Year metric tons 1960 4549642 1961 4760127 1962 4911804 1963 5255575.1 1964 5578831.1 1965 5760259.4 1966 5816244.8 1967 6312550 1968 6908932 1969 6488954 1970 6576532 1971 6627754 1972 6641896 1973 6877278 1974 7384543 1975 7315642 1976 7279035 1977 6734878 1978 6535941.100000001 1979 6373310.7 1980 6915035.9 1981 6924351.649999999 1982 7116674.1 1983 7168965.619999999 1984 7215976.57 1985 7077973.33 1986 7146600 1987 7016010.16 1988 7327214.76 1989 7053539.9 1990 6164980.17 1991 6259523.850000001 1992 7090236.28 1993 6686019.27 1994 6923693.609999999 1995 7281611.049999999 1996 6657097.600000001 1997 6729400.89 1998 6466986.98 1999 6125584.6899999995 2000 6092449.39 2001 6200808.220000001 2002 5864002.04 2003 5391909.34 2004 5400705.32 2005 5191204.59 2006 5183652.96 2007 4784766.89 2008 4675950.949999999 2009 4735872.209999999 2010 4879132.14 2011 4601204.470000001 2012 4091533.6000000006 2013 4451318.54 2014 4736613.600000001 2015 4721230.49 2016 4551848.0200000005 2017 4911529.59 2018 4687476.380000001 2019 4225315.7 2020 3995680.5599999996 2021 3734627.7899999996 2022 3657528.9499999997