Quarter	Millions of US Dollars
1987-01-01	372
1987-04-01	417
1987-07-01	437
1987-10-01	576
1988-01-01	574
1988-04-01	560
1988-07-01	631
1988-10-01	708
1989-01-01	685
1989-04-01	722
1989-07-01	800
1989-10-01	897
1990-01-01	1051
1990-04-01	1183
1990-07-01	1409
1990-10-01	1460
1991-01-01	1479
1991-04-01	1547
1991-07-01	1875
1991-10-01	2021
1992-01-01	2195
1992-04-01	2414
1992-07-01	2720
1992-10-01	2217
1993-01-01	2452
1993-04-01	2300
1993-07-01	2589
1993-10-01	2481
1994-01-01	2636
1994-04-01	2813
1994-07-01	3073
1994-10-01	3062
1995-01-01	3443
1995-04-01	3572
1995-07-01	3742
1995-10-01	3676
1996-01-01	3932
1996-04-01	4009
1996-07-01	4129
1996-10-01	4227
1997-01-01	4190
1997-04-01	4438
1997-07-01	4620
1997-10-01	4503
1998-01-01	4728
1998-04-01	4937
1998-07-01	5393
1998-10-01	5398
1999-01-01	5300
1999-04-01	5332
1999-07-01	5764
1999-10-01	5781
2000-01-01	5674
2000-04-01	5581
2000-07-01	5196
2000-10-01	5246
2001-01-01	4693
2001-04-01	4355
2001-07-01	4720
2001-10-01	4921
2002-01-01	5432
2002-04-01	6508
2002-07-01	6694
2002-10-01	7356
2003-01-01	8276
2003-04-01	8460
2003-07-01	9144
2003-10-01	10187
2004-01-01	10310
2004-04-01	10762
2004-07-01	11326
2004-10-01	13996
2005-01-01	14290
2005-04-01	14151
2005-07-01	15881
2005-10-01	16328
2006-01-01	14847
2006-04-01	15028
2006-07-01	16878
2006-10-01	18062
2007-01-01	19526
2007-04-01	22325
2007-07-01	23712
2007-10-01	25445
2008-01-01	19343
2008-04-01	21907
2008-07-01	17850
2008-10-01	12421
2009-01-01	12367
2009-04-01	11546
2009-07-01	12063
2009-10-01	12258
2010-01-01	11416
2010-04-01	13540
2010-07-01	15793
2010-10-01	15611
2011-01-01	16231
2011-04-01	16365
2011-07-01	15737
2011-10-01	16683
2012-01-01	16366
2012-04-01	16642
2012-07-01	16767
2012-10-01	16237
2013-01-01	17287
2013-04-01	17324
2013-07-01	17663
2013-10-01	18727
2014-01-01	18879
2014-04-01	18777
2014-07-01	17744
2014-10-01	17427
2015-01-01	16202
2015-04-01	16955
2015-07-01	18084
2015-10-01	17794
2016-01-01	19042
2016-04-01	19061
2016-07-01	20850
2016-10-01	21004
2017-01-01	20916
2017-04-01	23332
2017-07-01	22738
2017-10-01	22670
2018-01-01	24428