Year	US Dollars, Sum Over Component Sub-periods
1980-01-01	-6007000000
1981-01-01	-5200000000
1982-01-01	-4700000000
1983-01-01	-3517000000
1984-01-01	-1808000000
1985-01-01	-1693000000
1986-01-01	3413000000
1987-01-01	7205000000
1988-01-01	11172000000
1989-01-01	3923000000
1990-01-01	-2298000000
1991-01-01	-6448000000
1992-01-01	-412000000
1993-01-01	3731000000
1994-01-01	-3114000000
1995-01-01	-4420000000
1996-01-01	-15462000000
1997-01-01	-3861000000
1998-01-01	43237000000
1999-01-01	27893000000
2000-01-01	18656000000
2001-01-01	13029000000
2002-01-01	15203000000
2003-01-01	24028000000
2004-01-01	39661000000
2005-01-01	32857000000
2006-01-01	31434000000
2007-01-01	37129000000
2008-01-01	5170000000
2009-01-01	37866000000
2010-01-01	40083000000
2011-01-01	31660000000
2012-01-01	39817000000
2013-01-01	60696000000