Year US Dollars 1977 -4922222.22222 1978 -3888888.88889 1979 -9592592.59259 1980 -14518518.51852 1981 -16433333.33333 1982 -18418518.51852 1983 -26500000 1984 -19629629.62963 1985 -17537037.03704 1986 -14681481.48148 1987 -22218518.51852 1988 -31703703.7037 1989 -40196296.2963 1990 -49985185.18519 1991 -35007407.40741 1992 -12329629.62963 1993 -25366666.66667 1994 -22181481.48148 1995 -53681481.48148 1996 -65659259.25926 1997 -55974493.01153 1998 -48081414.74808 1999 -59296333.37041 2000 -98846995.14329 2001 -88975271.56786 2002 -103078634.18974 2003 -90717643.5695 2004 -47700518.51852 2005 -53470851.85185 2006 -84981370.37037 2007 -113299629.62963 2008 -201565148.14815 2009 -190810407.40741 2010 -155126851.85185 2011 -112931370.37037 2012 -73219888.88889 2013 -55099925.92593 2014 44592000 2015 12780370.37037 2016 4155592.59259