Year current US$ 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 0 1999 0 2000 0 2001 0 2002 0 2003 0 2004 0 2005 0 2006 0 2007 0 2008 1984873.48998007 2009 963933.695846081 2010 1497856.51290722 2011 2183791.98898141 2012 2059875.41360513 2013 3357002.73313943 2014 3450116.97259982 2015 1742737.71810711 2016 1937901.1287858 2017 3189.7986384365 2018 3756.5681881399 2019 2998.84508911437 2020 2689.06129416153 2021 5469.6559273734