Year metric tons 1961 3695000 1962 3696000 1963 3378000 1964 3732000 1965 3785000 1966 3489000 1967 3826000 1968 3916000 1969 4038000 1970 3512000 1971 3319000 1972 3950000 1973 4270000 1974 4351000 1975 4481000 1976 4624000 1977 4147000 1978 4382000 1979 4214000 1980 4072000 1981 3893000 1982 3724000 1983 3591000 1984 3418000 1985 3242000 1986 3084000 1987 3394000 1988 2997000 1989 2834000 1990 2705000 1991 2721302.33 1992 2470000 1993 2981774.06 1994 3144000 1995 3242179.28 1996 3241914.75 1997 3682722.57 1998 3875506.12 1999 3256395.77 2000 1940000 2001 2108000 2002 3737000 2003 4381000 2004 3560000 2005 5425000 2006 4638000 2007 5786000 2008 3950000 2009 6514000 2010 5957000 2011 4681020 2012 6582000 2013 6772235 2014 7012523.28 2015 6010288 2016 5708330.42 2017 5059633.97 2018 4304555.5 2019 5771861 2020 6241828 2021 4970609.31 2022 4824671.6