Quarter	Millions of US Dollars
1976-04-01	24
1986-04-01	-24
1989-04-01	16
1992-04-01	45
1993-04-01	-19
1995-04-01	-18
1996-04-01	-3
1996-07-01	46
1997-01-01	11
1997-04-01	130
1997-07-01	150
1998-01-01	150
1998-04-01	169
1998-10-01	209
1999-01-01	4
1999-04-01	-105
1999-07-01	33
1999-10-01	404
2000-01-01	12
2000-04-01	-55
2000-07-01	-146
2000-10-01	-35
2001-01-01	-160
2001-04-01	62
2001-07-01	-32
2001-10-01	253
2002-01-01	534
2002-04-01	682
2002-07-01	14
2002-10-01	2165
2003-01-01	2344
2003-04-01	160
2003-07-01	9
2003-10-01	31
2004-01-01	480
2004-04-01	928
2004-07-01	931
2004-10-01	627
2005-01-01	244
2005-04-01	-162
2005-07-01	-587
2005-10-01	459
2006-01-01	107
2006-04-01	370
2006-07-01	554
2006-10-01	1477
2007-01-01	1612
2007-04-01	1881
2007-07-01	785
2007-10-01	-302
2008-01-01	-12
2008-04-01	1681
2008-07-01	4311
2008-10-01	-32
2009-01-01	-831
2009-04-01	3342
2009-07-01	-980
2009-10-01	2989
2010-01-01	259
2010-04-01	5341
2010-07-01	-400
2010-10-01	2012
2011-01-01	3881
2011-04-01	1493
2011-07-01	-310
2011-10-01	78
2012-01-01	401
2012-04-01	1744
2012-07-01	3373
2012-10-01	6223
2013-01-01	2392
2013-04-01	9970
2013-07-01	-1375
2013-10-01	2945
2014-01-01	498
2014-04-01	-502
2014-07-01	-1432
2014-10-01	1125
2015-01-01	58
2015-04-01	-982
2015-07-01	-93
2015-10-01	-139
2016-01-01	185
2016-04-01	285
2016-07-01	-216
2016-10-01	1665
2017-01-01	-955
2017-04-01	-1072
2017-07-01	822
2017-10-01	630
2018-01-01	-1817
2018-04-01	-2216