Year	US Dollars, Monthly Level
1991-01-01	7008438748.746710
1992-01-01	9947065510.118040
1993-01-01	14476443084.238900
1994-01-01	17338042744.422900
1995-01-01	25173683528.695400
1996-01-01	27786208668.506900
1997-01-01	27053132854.511400
1998-01-01	28328888945.716698
1999-01-01	27782092201.957203
2000-01-01	32194050472.450000
2001-01-01	36537883361.100800
2002-01-01	40659644472.501800
2003-01-01	51170577600.276700
2004-01-01	67821989825.429500
2005-01-01	76172476330.037600
2006-01-01	93662693506.069000
2007-01-01	118612841009.254000
2008-01-01	142069577020.791020
2009-01-01	105514458145.510010
2010-01-01	126266344018.961000
2011-01-01	152146902031.959000
2012-01-01	142149937882.535980
2013-01-01	144520084548.938000
2014-01-01	154385802046.772000
2015-01-01	140858228661.761000
2016-01-01	143288121661.185000
2017-01-01	163175068895.662020