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 2 1988 2 1989 2 1990 6 1991 1 1992 17 1993 36 1994 72 1995 103 1996 119 1997 157 1998 172 1999 194 2000 113 2001 99 2002 157 2003 160 2004 709 2005 454 2006 475 2007 622 2008 473 2009 433 2010 499.98 2011 530 2012 550 2013 560.85 2014 711.07 2015 983.14 2016 947.63 2017 1632 2018 1245.99 2019 933.18 2020 3500.03 2021 4767.92 2022 5020