Quarter	Millions of US Dollars
1996-10-01	75
1997-01-01	75
1997-04-01	75
1997-07-01	75
1997-10-01	70
1998-01-01	70
1998-04-01	70
1998-07-01	70
1998-10-01	70
1999-01-01	70
1999-04-01	70
1999-07-01	70
2005-07-01	500
2005-10-01	500
2006-01-01	500
2006-04-01	500
2006-07-01	650
2006-10-01	850
2007-01-01	850
2007-04-01	975
2007-07-01	975
2007-10-01	975
2008-01-01	975
2008-04-01	975
2008-07-01	975
2008-10-01	975
2009-01-01	961
2009-04-01	961
2009-07-01	946
2009-10-01	946
2010-01-01	932
2010-04-01	932
2010-07-01	918
2010-10-01	918
2011-01-01	904
2011-04-01	904
2011-07-01	889
2011-10-01	1463
2012-01-01	1713
2012-04-01	1713
2012-07-01	1249
2012-10-01	1249
2013-01-01	2549
2013-04-01	2549
2013-07-01	2521
2013-10-01	2521
2014-01-01	2506
2014-04-01	2506
2014-07-01	2492
2014-10-01	2492
2015-01-01	3417
2015-04-01	3417
2015-07-01	3388
2015-10-01	3388
2016-01-01	3388
2016-04-01	3388
2016-07-01	3388
2016-10-01	3388
2017-01-01	3388
2017-04-01	3138
2017-07-01	3138
2017-10-01	3138
2018-01-01	3138
2018-04-01	3138