Year	US Dollars, Sum Over Component Sub-periods
1980-01-01	5920000000
1981-01-01	4973000000
1982-01-01	4201000000
1983-01-01	2971000000
1984-01-01	1832000000
1985-01-01	2756000000
1986-01-01	-3681000000
1987-01-01	-11489000000
1988-01-01	-13804000000
1989-01-01	-5615000000
1990-01-01	3555000000
1991-01-01	7063000000
1992-01-01	1482000000
1993-01-01	-1836000000
1994-01-01	5684000000
1995-01-01	9723000000
1996-01-01	22486000000
1997-01-01	13896000000
1998-01-01	-35909000000
1999-01-01	-19918000000
2000-01-01	-12768000000
2001-01-01	-10355000000
2002-01-01	-5923000000
2003-01-01	-14949000000
2004-01-01	-33714000000
2005-01-01	-17189000000
2006-01-01	-11025000000
2007-01-01	-21489000000
2008-01-01	-863000000
2009-01-01	-34941000000
2010-01-01	-27261000000
2011-01-01	-26753000000
2012-01-01	-51374000000
2013-01-01	-72443000000