Year	US Dollars, Monthly Level
1988-01-01	5834109017.634000
1989-01-01	6226700909.231930
1990-01-01	7636233836.508530
1991-01-01	8017076247.361130
1992-01-01	8205277855.376240
1993-01-01	7701374273.165649
1994-01-01	8436573057.941629
1995-01-01	10008624776.036500
1996-01-01	9521483940.609370
1997-01-01	9358952735.217009
1998-01-01	10072017650.812600
1999-01-01	11071880573.166199
2000-01-01	11307771422.584200
2001-01-01	12360634721.210100
2002-01-01	12655674861.815100
2003-01-01	16189735263.563002
2004-01-01	19927025039.061500
2005-01-01	22343826906.299800
2006-01-01	27271448596.843100
2007-01-01	28048566236.789500
2008-01-01	32178034912.982400
2009-01-01	25248728748.837800
2010-01-01	24657306960.494100
2011-01-01	28878148214.793700
2012-01-01	27226792519.527000
2013-01-01	26616930446.394300
2014-01-01	26674594181.216103
2015-01-01	23233427649.840300
2016-01-01	21800668356.495300
2017-01-01	22776644989.098797