Quarter	Millions of US Dollars
1981-07-01	43
1983-07-01	50
1983-10-01	22
1984-04-01	51
1984-07-01	25
1985-04-01	180
1985-10-01	145
1986-04-01	159
1986-07-01	20
1986-10-01	125
1987-04-01	53
1987-07-01	205
1987-10-01	50
1988-07-01	50
1988-10-01	60
1989-04-01	-45
1989-07-01	-36
1989-10-01	50
1990-01-01	250
1990-07-01	70
1990-10-01	62
1991-01-01	88
1991-04-01	259
1991-07-01	200
1991-10-01	436
1992-01-01	233
1992-04-01	80
1992-07-01	662
1992-10-01	778
1993-01-01	235
1993-04-01	351
1993-07-01	365
1993-10-01	2134
1994-01-01	532
1994-04-01	323
1994-07-01	424
1994-10-01	48
1995-01-01	54
1995-04-01	921
1995-07-01	210
1995-10-01	32
1996-01-01	842
1996-04-01	1067
1996-07-01	804
1996-10-01	429
1997-01-01	413
1997-04-01	1639
1997-07-01	1587
1997-10-01	744
1998-01-01	58
1998-04-01	-252
1998-07-01	-491
1998-10-01	-395
1999-01-01	-157
1999-04-01	49
1999-07-01	137
1999-10-01	367
2000-01-01	-6
2000-04-01	615
2000-07-01	673
2000-10-01	-173
2001-01-01	-93
2001-04-01	1230
2001-07-01	-86
2001-10-01	1005
2002-01-01	1144
2002-04-01	251
2002-07-01	231
2002-10-01	-559
2003-01-01	-153
2003-04-01	611
2003-07-01	164
2003-10-01	-957
2004-01-01	181
2004-04-01	1939
2004-07-01	-130
2004-10-01	-182
2005-01-01	-121
2005-04-01	852
2005-07-01	1242
2005-10-01	906
2006-01-01	245
2006-04-01	569
2006-07-01	1519
2006-10-01	410
2007-01-01	-1077
2007-04-01	1577
2007-07-01	-892
2007-10-01	341
2008-01-01	-352
2008-04-01	598
2008-07-01	-200
2008-10-01	184
2009-01-01	850
2009-04-01	2038
2009-07-01	1901
2009-10-01	1085
2010-01-01	-180
2010-04-01	-343
2010-07-01	193
2010-10-01	3128
2011-01-01	883
2011-04-01	2717
2011-07-01	1106
2011-10-01	272
2012-01-01	1384
2012-04-01	1151
2012-07-01	2164
2012-10-01	-238
2013-01-01	1388
2013-04-01	-1241
2013-07-01	2129
2013-10-01	4269
2014-01-01	1435
2014-04-01	-159
2014-07-01	1172
2014-10-01	1798
2015-01-01	-557
2015-04-01	448
2015-07-01	-770
2015-10-01	-1686
2016-01-01	-416
2016-04-01	895
2016-07-01	-635
2016-10-01	-623
2017-01-01	1116
2017-04-01	-1194
2017-07-01	682
2017-10-01	901
2018-01-01	413
2018-04-01	1924