Year	US Dollars, Sum Over Component Sub-periods
1988-01-01	-1585240000
1989-01-01	-1694240000
1990-01-01	553640000
1991-01-01	1191970000
1992-01-01	3160290000
1993-01-01	3889130000
1994-01-01	2330270000
1995-01-01	1276470000
1996-01-01	2662180000
1997-01-01	672310000
1998-01-01	-1485220000
1999-01-01	3326120000
2000-01-01	2552540000
2001-01-01	4115700000
2002-01-01	4984860000
2003-01-01	7343470000
2004-01-01	5743740000
2005-01-01	11125750000
2006-01-01	8176500000
2007-01-01	4234800000
2008-01-01	9058140000
2009-01-01	10550770000
2010-01-01	18436760000
2011-01-01	18890870000
2012-01-01	18129710000
2013-01-01	24216080000