Year current US$ 1970 0 1971 0 1972 0 1973 18204.1229922606 1974 143196.181529795 1975 44431.1779890892 1976 76433.7239284424 1977 212294.214362422 1978 259086.754509492 1979 341004.726534117 1980 367795.436277345 1981 4545.27969856683 1982 3074.74992770336 1983 12127.8562890185 1984 39185.9618168895 1985 21356.9599811847 1986 30443.6174722583 1987 49815.8285999788 1988 42999.5586452956 1989 8608.1187062645 1990 3807.18770337217 1991 20707.7136227962 1992 0 1993 0 1994 0 1995 2107587.69042888 1996 5979860.21671857 1997 0 1998 0 1999 0 2000 0 2001 580759.711435868 2002 1219548.77488001 2003 461406.661911859 2004 652708.824530135 2005 1047462.73183521 2006 2915683.86802945 2007 3298824.59518761 2008 4233424.58686295 2009 3380047.37682489 2010 2763546.10079044 2011 6379202.41892478 2012 7392397.44400728 2013 3983973.38988975 2014 5288001.19528521 2015 3367918.94145511 2016 3125208.98484407 2017 5623618.69354703 2018 0 2019 0 2020 0 2021 0