Quarter	Millions of US Dollars
1987-01-01	294
1987-04-01	319
1987-07-01	315
1987-10-01	419
1988-01-01	396
1988-04-01	356
1988-07-01	392
1988-10-01	442
1989-01-01	394
1989-04-01	444
1989-07-01	495
1989-10-01	530
1990-01-01	619
1990-04-01	702
1990-07-01	836
1990-10-01	836
1991-01-01	764
1991-04-01	767
1991-07-01	928
1991-10-01	1011
1992-01-01	1060
1992-04-01	1154
1992-07-01	1301
1992-10-01	1075
1993-01-01	1144
1993-04-01	1059
1993-07-01	1226
1993-10-01	1150
1994-01-01	1215
1994-04-01	1308
1994-07-01	1436
1994-10-01	1380
1995-01-01	1418
1995-04-01	1435
1995-07-01	1607
1995-10-01	1558
1996-01-01	1612
1996-04-01	1589
1996-07-01	1634
1996-10-01	1606
1997-01-01	1625
1997-04-01	1747
1997-07-01	1836
1997-10-01	1619
1998-01-01	1698
1998-04-01	1786
1998-07-01	1946
1998-10-01	1791
1999-01-01	1613
1999-04-01	1585
1999-07-01	1671
1999-10-01	1569
2000-01-01	1524
2000-04-01	1382
2000-07-01	1237
2000-10-01	1168
2001-01-01	1111
2001-04-01	1001
2001-07-01	1084
2001-10-01	1097
2002-01-01	1200
2002-04-01	1243
2002-07-01	1325
2002-10-01	1401
2003-01-01	1545
2003-04-01	1597
2003-07-01	1851
2003-10-01	1868
2004-01-01	2000
2004-04-01	1927
2004-07-01	2064
2004-10-01	2261
2005-01-01	2197
2005-04-01	1941
2005-07-01	2149
2005-10-01	2205
2006-01-01	1707
2006-04-01	1582
2006-07-01	1980
2006-10-01	1906
2007-01-01	1951
2007-04-01	2194
2007-07-01	2270
2007-10-01	2276
2008-01-01	1862
2008-04-01	2358
2008-07-01	2177
2008-10-01	2714
2009-01-01	2991
2009-04-01	2922
2009-07-01	3441
2009-10-01	3869
2010-01-01	3658
2010-04-01	5722
2010-07-01	6976
2010-10-01	6784
2011-01-01	7281
2011-04-01	7266
2011-07-01	6953
2011-10-01	7113
2012-01-01	6995
2012-04-01	7166
2012-07-01	7277
2012-10-01	7057
2013-01-01	7584
2013-04-01	7301
2013-07-01	7622
2013-10-01	7956
2014-01-01	7996
2014-04-01	7951
2014-07-01	7559
2014-10-01	7508
2015-01-01	7020
2015-04-01	7164
2015-07-01	7776
2015-10-01	7517
2016-01-01	7953
2016-04-01	7737
2016-07-01	8609
2016-10-01	8380
2017-01-01	8055
2017-04-01	8840
2017-07-01	8471
2017-10-01	8240
2018-01-01	8469