Quarter	Millions of US Dollars
1998-10-01	5365
1999-01-01	5637
1999-04-01	5089
1999-07-01	5356
1999-10-01	4882
2000-01-01	5172
2000-04-01	5110
2000-07-01	4605
2000-10-01	4543
2001-01-01	4562
2001-04-01	4892
2001-07-01	4912
2001-10-01	5054
2002-01-01	5347
2002-04-01	6211
2002-07-01	6148
2002-10-01	7386
2003-01-01	7860
2003-04-01	8234
2003-07-01	8136
2003-10-01	8934
2004-01-01	8837
2004-04-01	8869
2004-07-01	9297
2004-10-01	10788
2005-01-01	11153
2005-04-01	9908
2005-07-01	10303
2005-10-01	10318
2006-01-01	10643
2006-04-01	11525
2006-07-01	11710
2006-10-01	12206
2007-01-01	13540
2007-04-01	12637
2007-07-01	13002
2007-10-01	13518
2008-01-01	15958
2008-04-01	15201
2008-07-01	13687
2008-10-01	13650
2009-01-01	14954
2009-04-01	17917
2009-07-01	23567
2009-10-01	23516
2010-01-01	23226
2010-04-01	22246
2010-07-01	24748
2010-10-01	24318
2011-01-01	29970
2011-04-01	28971
2011-07-01	26751
2011-10-01	26386
2012-01-01	26239
2012-04-01	24715
2012-07-01	23912
2012-10-01	26457
2013-01-01	25756
2013-04-01	29499
2013-07-01	29956
2013-10-01	34890
2014-01-01	38697
2014-04-01	39567
2014-07-01	36567
2014-10-01	36482
2015-01-01	33057
2015-04-01	33179
2015-07-01	35419
2015-10-01	34001
2016-01-01	35658
2016-04-01	34723
2016-07-01	35427
2016-10-01	31411
2017-01-01	33307
2017-04-01	35956
2017-07-01	37201
2017-10-01	35418
2018-01-01	37904