Year US Dollars 1960 -44385302.13939 1961 -34249085.45379 1962 -34217890.7752 1963 -54261839.98805 1964 -53164814.63398 1965 -56584742.6849 1966 -53145783.0646 1967 -38160008.14475 1968 -51994464.26469 1969 -52843618.23462 1970 -26965836.57569 1971 -78939361.32416 1972 -54472051.23973 1973 -76551270.06791 1974 -89758416.72595 1975 -114851459.23223 1976 -51512445.96939 1977 -85015374.76558 1978 -184382967.38905 1979 -547650299.17645 1980 -662712925.60414 1981 -406614371.22387 1982 -332918780.13864 1983 -244531486.29639 1984 -135976235.7093 1985 -236240624.77594 1986 -110727957.42775 1987 -152435269.8557 1988 -166081973.41118 1989 -95479431.84564 1990 -352060299.52441 1991 -227615301.6302 1992 -250530933.36173 1993 -313414396.35904 1994 -225260294.76392 1995 -239424819.04496 1996 -220200103.21941 1997 -286989918.6507 1998 -290005519.44505 1999 -287890767.81075 2000 -284070386.01217 2001 -145562118.06522 2002 -288700255.38806 2003 -491992100.15249 2004 -647933027.97035 2005 -873833477.33214 2006 -884753534.01437 2007 -1596607717.03923 2008 -2858458479.85695 2009 -2501656523.0509 2010 -1577891815.59367 2011 -1542357418.76706 2012 -1042187173.3635 2013 -921008986.8922 2014 -467544573.84814 2015 -337810538.9032 2016 -226286728.90295 2017 -415914828.68063