Quarter	Millions of US Dollars
1999-04-01	232
1999-07-01	25
1999-10-01	95
2000-01-01	-162
2000-04-01	7
2000-07-01	-105
2000-10-01	-160
2001-01-01	-82
2001-04-01	83
2001-07-01	-32
2001-10-01	12
2002-01-01	278
2002-04-01	149
2002-07-01	-27
2002-10-01	0
2003-01-01	-6
2003-04-01	244
2003-07-01	51
2003-10-01	337
2004-01-01	296
2004-04-01	970
2004-07-01	347
2004-10-01	390
2005-01-01	1224
2005-04-01	2403
2005-07-01	1134
2005-10-01	149
2006-01-01	1005
2006-04-01	1355
2006-07-01	1571
2006-10-01	904
2007-01-01	1936
2007-04-01	5446
2007-07-01	2015
2007-10-01	2313
2008-01-01	1104
2008-04-01	1848
2008-07-01	-3859
2008-10-01	-5973
2009-01-01	3502
2009-04-01	4954
2009-07-01	2491
2009-10-01	1805
2010-01-01	2231
2010-04-01	240
2010-07-01	2308
2010-10-01	1065
2011-01-01	768
2011-04-01	-1159
2011-07-01	-1187
2011-10-01	-1581
2012-01-01	1500
2012-04-01	-2519
2012-07-01	1653
2012-10-01	1697
2013-01-01	1303
2013-04-01	57
2013-07-01	1212
2013-10-01	-179
2014-01-01	300
2014-04-01	-2
2014-07-01	1145
2014-10-01	-4030
2015-01-01	555
2015-04-01	-815
2015-07-01	301
2015-10-01	-152
2016-01-01	86
2016-04-01	1580
2016-07-01	3601
2016-10-01	529
2017-01-01	2215
2017-04-01	2239
2017-07-01	1705
2017-10-01	1053
2018-01-01	1882