Year current US$ 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 0 1991 0 1992 0 1993 0 1994 0 1995 0 1996 0 1997 0 1998 4809.39732376472 1999 6507.72541273085 2000 9990.44432129517 2001 550.637927684752 2002 1534.8515443492 2003 2211.9184857676 2004 0 2005 0 2006 38763.6760225887 2007 40427.6108498676 2008 47590.8939907553 2009 57169.212400522 2010 0 2011 0 2012 0 2013 0 2014 0 2015 0 2016 0 2017 0 2018 0 2019 0 2020 0 2021 0