Quarter	Millions of US Dollars
2001-01-01	7627
2001-04-01	7765
2001-07-01	7007
2001-10-01	5556
2002-01-01	6072
2002-04-01	6387
2002-07-01	6523
2002-10-01	7756
2003-01-01	8606
2003-04-01	9077
2003-07-01	9895
2003-10-01	10890
2004-01-01	10992
2004-04-01	11181
2004-07-01	11671
2004-10-01	13956
2005-01-01	12675
2005-04-01	12649
2005-07-01	13162
2005-10-01	12785
2006-01-01	12962
2006-04-01	11688
2006-07-01	11965
2006-10-01	13467
2007-01-01	13617
2007-04-01	14145
2007-07-01	14816
2007-10-01	15967
2008-01-01	12916
2008-04-01	13215
2008-07-01	13293
2008-10-01	12108
2009-01-01	13098
2009-04-01	17068
2009-07-01	19525
2009-10-01	20515
2010-01-01	22360
2010-04-01	22801
2010-07-01	25940
2010-10-01	28396
2011-01-01	28312
2011-04-01	28925
2011-07-01	24501
2011-10-01	24589
2012-01-01	26261
2012-04-01	25298
2012-07-01	25873
2012-10-01	26256
2013-01-01	25204
2013-04-01	24272
2013-07-01	24771
2013-10-01	24417
2014-01-01	24434
2014-04-01	25222
2014-07-01	23596
2014-10-01	23694
2015-01-01	22867
2015-04-01	23544
2015-07-01	20769
2015-10-01	18697
2016-01-01	19928
2016-04-01	20053
2016-07-01	21961
2016-10-01	22231
2017-01-01	23066
2017-04-01	23635
2017-07-01	23245
2017-10-01	25098
2018-01-01	26178