Quarter	Millions of US Dollars
1988-04-01	0
1988-07-01	0
1988-10-01	0
1989-01-01	0
1989-04-01	0
1989-07-01	0
1989-10-01	0
1990-01-01	0
1990-04-01	0
1990-07-01	0
1990-10-01	0
1991-01-01	0
1991-04-01	0
1991-07-01	0
1991-10-01	0
1992-01-01	0
1992-04-01	0
1992-07-01	0
1992-10-01	0
1993-01-01	0
1993-04-01	0
1993-07-01	0
1993-10-01	0
1994-01-01	0
1994-04-01	494
1994-07-01	659
1994-10-01	1198
1995-01-01	1288
1995-04-01	1163
1995-07-01	1433
1995-10-01	1548
1996-01-01	2003
1996-04-01	1820
1996-07-01	1581
1996-10-01	1367
1997-01-01	840
1997-04-01	943
1997-07-01	1567
1997-10-01	2987
1998-01-01	2929
1998-04-01	3563
1998-07-01	3423
1998-10-01	1597
1999-01-01	2624
1999-04-01	1640
1999-07-01	1519
1999-10-01	1768
2000-01-01	562
2000-04-01	1275
2000-07-01	916
2000-10-01	1968
2001-01-01	2102
2001-04-01	2556
2001-07-01	2686
2001-10-01	2089
2002-01-01	2686
2002-04-01	2932
2002-07-01	3398
2002-10-01	3566
2003-01-01	4754
2003-04-01	3748
2003-07-01	3767
2003-10-01	3828
2004-01-01	2507
2004-04-01	3207
2004-07-01	3234
2004-10-01	2952
2005-01-01	1390
2005-04-01	1192
2005-07-01	704
2005-10-01	2986
2006-01-01	2527
2006-04-01	2907
2006-07-01	3499
2006-10-01	1588
2007-01-01	4715
2007-04-01	3725
2007-07-01	3159
2007-10-01	3786
2008-01-01	600
2008-04-01	1850
2008-07-01	2708
2008-10-01	2085
2009-01-01	3379
2009-04-01	3761
2009-07-01	2964
2009-10-01	2941
2010-01-01	2511
2010-04-01	1670
2010-07-01	1774
2010-10-01	1752
2011-01-01	1750
2011-04-01	1000
2011-07-01	2350
2011-10-01	2294
2012-01-01	2836
2012-04-01	2759
2012-07-01	1500
2012-10-01	1500
2013-01-01	3030
2013-04-01	3058
2013-07-01	3101
2013-10-01	3129
2014-01-01	2750
2014-04-01	2750
2014-07-01	2750
2014-10-01	2750
2015-01-01	807
2015-04-01	839
2015-07-01	3170
2015-10-01	3147
2016-01-01	4038
2016-04-01	3995
2016-07-01	3924
2016-10-01	3831
2017-01-01	3750
2017-04-01	6000
2017-07-01	3750
2017-10-01	6250
2018-01-01	6250
2018-04-01	5457