Year	US Dollars, Monthly Level
1996-01-01	19038328783.672500
1997-01-01	20762089189.517400
1998-01-01	19853552180.566300
1999-01-01	15968718800.783500
2000-01-01	18513997649.752400
2001-01-01	17791470573.418600
2002-01-01	17127839707.360600
2003-01-01	17841916725.209600
2004-01-01	22778944019.570103
2005-01-01	30659271538.917700
2006-01-01	36455976079.886600
2007-01-01	44316539476.421394
2008-01-01	58272200867.260500
2009-01-01	40023178053.338100
2010-01-01	55025228457.206800
2011-01-01	70702929314.654500
2012-01-01	75357243199.529710
2013-01-01	74680666438.339900
2014-01-01	68585750679.837204
2015-01-01	58558451956.135994
2016-01-01	55326641934.341900
2017-01-01	61424060860.231600