Year metric tons 1960 0 1961 0 1962 0 1963 0 1964 0 1965 0 1966 0 1967 0 1968 0 1969 0 1970 0 1971 0 1972 0 1973 0 1974 0 1975 0 1976 0 1977 0 1978 0 1979 0 1980 0 1981 0 1982 0 1983 0 1984 0 1985 0 1986 0 1987 0 1988 0 1989 0 1990 20 1991 20 1992 22 1993 57 1994 66 1995 67 1996 67 1997 62 1998 62 1999 65 2000 70 2001 70 2002 88 2003 142 2004 192 2005 192 2006 273.5 2007 360.5 2008 605.6 2009 665.6 2010 695.64 2011 532.13 2012 679.35 2013 671.56 2014 647.34 2015 625.73 2016 525.2 2017 506.93 2018 342.48 2019 388.96 2020 320.72 2021 321 2022 340