Year	US Dollars, Sum Over Component Sub-periods
1980-01-01	-841000000
1981-01-01	-297000000
1982-01-01	-93000000
1983-01-01	74000000
1984-01-01	-875000000
1985-01-01	41000000
1986-01-01	46000000
1987-01-01	-886000000
1988-01-01	-8857000000
1989-01-01	-3190000000
1990-01-01	1186000000
1991-01-01	1143000000
1992-01-01	-3708000000
1993-01-01	-3008000000
1994-01-01	-4646000000
1995-01-01	-7045000000
1996-01-01	-1389000000
1997-01-01	11922000000
1998-01-01	-30975000000
1999-01-01	-22983000000
2000-01-01	-23771000000
2001-01-01	-7576000000
2002-01-01	-11799000000
2003-01-01	-25849000000
2004-01-01	-38711000000
2005-01-01	-19806000000
2006-01-01	-22113000000
2007-01-01	-15128000000
2008-01-01	56446000000
2009-01-01	-68666000000
2010-01-01	-26971000000
2011-01-01	-13953000000
2012-01-01	-13185000000
2013-01-01	-14479000000