Quarter	Millions of US Dollars
1996-10-01	1200
1997-01-01	1200
1997-04-01	1200
1997-07-01	1200
1997-10-01	1200
1998-01-01	1200
1998-04-01	1200
1998-07-01	1200
1998-10-01	1200
1999-01-01	1200
1999-04-01	2200
1999-07-01	2200
1999-10-01	2200
2000-01-01	2200
2000-04-01	3600
2000-07-01	3600
2000-10-01	3600
2001-01-01	3600
2001-04-01	3600
2001-07-01	3600
2001-10-01	3600
2002-01-01	3527
2002-04-01	3527
2002-07-01	3491
2002-10-01	3491
2003-01-01	3455
2003-04-01	3455
2003-07-01	3455
2003-10-01	4155
2004-01-01	4747
2004-04-01	4747
2004-07-01	4710
2004-10-01	4710
2005-01-01	4674
2005-04-01	4674
2005-07-01	6888
2005-10-01	6888
2006-01-01	6851
2006-04-01	8001
2006-07-01	9515
2006-10-01	11005
2007-01-01	11005
2007-04-01	11005
2007-07-01	11305
2007-10-01	11305
2008-01-01	11442
2008-04-01	11606
2008-07-01	11606
2008-10-01	11606
2009-01-01	11606
2009-04-01	15106
2009-07-01	16591
2009-10-01	25191
2010-01-01	25111
2010-04-01	25660
2010-07-01	29730
2010-10-01	33926
2011-01-01	33852
2011-04-01	33231
2011-07-01	33303
2011-10-01	37791
2012-01-01	38223
2012-04-01	38769
2012-07-01	43125
2012-10-01	49310
2013-01-01	52221
2013-04-01	54683
2013-07-01	54685
2013-10-01	57695
2014-01-01	58337
2014-04-01	56018
2014-07-01	56276
2014-10-01	56517
2015-01-01	54330
2015-04-01	56154
2015-07-01	55070
2015-10-01	53271
2016-01-01	56727
2016-04-01	70280
2016-07-01	73360
2016-10-01	70213
2017-01-01	70143
2017-04-01	71671
2017-07-01	64976
2017-10-01	63161
2018-01-01	64711
2018-04-01	76896