Year	US Dollars, Monthly Level
1991-01-01	76526506157.27719
1992-01-01	63649686434.59710
1993-01-01	46127382740.23080
1994-01-01	50518400000.00000
1995-01-01	60945000000.00000
1996-01-01	68828300000.00000
1997-01-01	71789000000.00000
1998-01-01	57538000000.00000
1999-01-01	37263000000.00000
2000-01-01	42131000000.00000
2001-01-01	51319000000.00000
2002-01-01	58421000000.00000
2003-01-01	73214000000.00000
2004-01-01	94244000000.00000
2005-01-01	123840000000.00000
2006-01-01	163188000000.00000
2007-01-01	223083000000.00000
2008-01-01	288672000000.00000
2009-01-01	183923000000.00000
2010-01-01	245679000000.00000
2011-01-01	318555000000.00000
2012-01-01	335770000000.00000
2013-01-01	341269000000.00000
2014-01-01	307877000000.00000
2015-01-01	193019000000.00000
2016-01-01	191493000000.00000
2017-01-01	238126000000.00000