Quarter	Millions of US Dollars
1988-07-01	5117
1988-10-01	4396
1989-01-01	4378
1989-04-01	3343
1989-07-01	7286
1989-10-01	7208
1990-01-01	560
1990-04-01	-5218
1990-07-01	9899
1990-10-01	5238
1991-01-01	6433
1991-04-01	-2054
1991-07-01	5060
1991-10-01	6147
1992-01-01	1204
1992-04-01	4320
1992-07-01	1507
1992-10-01	5133
1993-01-01	3213
1993-04-01	-2324
1993-07-01	3737
1993-10-01	4396
1994-01-01	-249
1994-04-01	-5363
1994-07-01	1797
1994-10-01	6392
1995-01-01	2928
1995-04-01	2569
1995-07-01	3895
1995-10-01	6408
1996-01-01	3096
1996-04-01	657
1996-07-01	5616
1996-10-01	9381
1997-01-01	-3935
1997-04-01	4607
1997-07-01	6260
1997-10-01	-460
1998-01-01	924
1998-04-01	3446
1998-07-01	7441
1998-10-01	3937
1999-01-01	6035
1999-04-01	914
1999-07-01	6589
1999-10-01	2858
2000-01-01	5817
2000-04-01	-203
2000-07-01	-313
2000-10-01	72
2001-01-01	4362
2001-04-01	-2036
2001-07-01	2884
2001-10-01	6330
2002-01-01	3367
2002-04-01	4033
2002-07-01	13042
2002-10-01	-3875
2003-01-01	3441
2003-04-01	9662
2003-07-01	679
2003-10-01	12220
2004-01-01	16996
2004-04-01	3828
2004-07-01	11046
2004-10-01	16819
2005-01-01	17268
2005-04-01	10274
2005-07-01	1433
2005-10-01	19408
2006-01-01	15006
2006-04-01	14652
2006-07-01	16430
2006-10-01	10656
2007-01-01	11016
2007-04-01	33393
2007-07-01	84452
2007-10-01	47023
2008-01-01	29512
2008-04-01	35796
2008-07-01	14605
2008-10-01	57981
2009-01-01	-11783
2009-04-01	19838
2009-07-01	8292
2009-10-01	13994
2010-01-01	-3316
2010-04-01	15382
2010-07-01	9321
2010-10-01	28233
2011-01-01	16501
2011-04-01	18767
2011-07-01	63179
2011-10-01	20769
2012-01-01	67080
2012-04-01	14630
2012-07-01	38310
2012-10-01	-10025
2013-01-01	-645
2013-04-01	3259
2013-07-01	17192
2013-10-01	22313
2014-01-01	38168
2014-04-01	45786
2014-07-01	46153
2014-10-01	54627
2015-01-01	35531
2015-04-01	-14165
2015-07-01	33430
2015-10-01	-2146
2016-01-01	37191
2016-04-01	8364
2016-07-01	22367
2016-10-01	-22163
2017-01-01	26567
2017-04-01	2985
2017-07-01	-8929
2017-10-01	21048
2018-01-01	16251