Quarter	Millions of US Dollars
1999-01-01	1222
1999-04-01	1323
1999-07-01	1273
1999-10-01	1357
2000-01-01	1381
2000-04-01	1324
2000-07-01	1325
2000-10-01	1275
2001-01-01	1229
2001-04-01	1462
2001-07-01	1790
2001-10-01	1887
2002-01-01	2005
2002-04-01	1902
2002-07-01	1798
2002-10-01	1821
2003-01-01	2071
2003-04-01	2314
2003-07-01	2420
2003-10-01	2449
2004-01-01	2895
2004-04-01	3278
2004-07-01	3486
2004-10-01	3713
2005-01-01	5149
2005-04-01	6148
2005-07-01	7580
2005-10-01	8417
2006-01-01	8662
2006-04-01	9444
2006-07-01	9877
2006-10-01	10588
2007-01-01	11211
2007-04-01	13117
2007-07-01	14286
2007-10-01	16147
2008-01-01	18924
2008-04-01	20708
2008-07-01	19531
2008-10-01	16259
2009-01-01	15509
2009-04-01	17999
2009-07-01	20901
2009-10-01	21247
2010-01-01	22544
2010-04-01	21934
2010-07-01	25245
2010-10-01	25748
2011-01-01	26023
2011-04-01	26816
2011-07-01	25494
2011-10-01	26089
2012-01-01	27400
2012-04-01	26797
2012-07-01	27587
2012-10-01	29053
2013-01-01	29881
2013-04-01	30122
2013-07-01	30543
2013-10-01	30797
2014-01-01	29862
2014-04-01	29985
2014-07-01	29443
2014-10-01	27351
2015-01-01	26128
2015-04-01	27779
2015-07-01	27534
2015-10-01	27390
2016-01-01	30410
2016-04-01	28831
2016-07-01	29916
2016-10-01	28387
2017-01-01	29280
2017-04-01	30597
2017-07-01	28511
2017-10-01	29563
2018-01-01	28857