Quarter	Millions of US Dollars
1972-04-01	0
1972-07-01	0
1972-10-01	0
1973-01-01	0
1973-04-01	0
1973-07-01	0
1973-10-01	0
1974-01-01	0
1974-04-01	0
1974-07-01	0
1974-10-01	0
1975-01-01	0
1975-04-01	0
1975-07-01	0
1975-10-01	0
1976-01-01	0
1976-04-01	0
1976-07-01	0
1976-10-01	0
1977-01-01	0
1977-04-01	0
1977-07-01	0
1977-10-01	0
1978-01-01	0
1978-04-01	0
1978-07-01	0
1978-10-01	0
1979-01-01	0
1979-04-01	0
1979-07-01	0
1979-10-01	0
1980-01-01	0
1980-04-01	0
1980-07-01	30
1980-10-01	55
1981-01-01	55
1981-04-01	109
1981-07-01	98
1981-10-01	98
1982-01-01	159
1982-04-01	128
1982-07-01	109
1982-10-01	104
1983-01-01	37
1983-04-01	12
1983-07-01	27
1983-10-01	15
1984-01-01	15
1984-04-01	40
1984-07-01	25
1984-10-01	55
1985-01-01	141
1985-04-01	116
1985-07-01	118
1985-10-01	146
1986-01-01	67
1986-04-01	73
1986-07-01	78
1986-10-01	2
1987-01-01	2
1987-04-01	2
1987-07-01	2
1987-10-01	82
1988-01-01	110
1988-04-01	101
1988-07-01	167
1988-10-01	295
1989-01-01	274
1989-04-01	404
1989-07-01	337
1989-10-01	203
1990-01-01	258
1990-04-01	214
1990-07-01	381
1990-10-01	379
1991-01-01	473
1991-04-01	477
1991-07-01	317
1991-10-01	321
1992-01-01	257
1992-04-01	214
1992-07-01	220
1992-10-01	140
1993-01-01	40
1993-04-01	78
1993-07-01	675
1993-10-01	617
1994-01-01	731
1994-04-01	659
1994-07-01	225
1994-10-01	225
1995-01-01	296
1995-04-01	299
1995-07-01	518
1995-10-01	515
1996-01-01	471
1996-04-01	471
1996-07-01	341
1996-10-01	193
1997-01-01	178
1997-04-01	118
1997-07-01	88
1997-10-01	174
1998-01-01	215
1998-04-01	344
1998-07-01	414
1998-10-01	471
1999-01-01	494
1999-04-01	525
1999-07-01	950
1999-10-01	1009
2000-01-01	1106
2000-04-01	2212
2000-07-01	1883
2000-10-01	2275
2001-01-01	2184
2001-04-01	2530
2001-07-01	3066
2001-10-01	2720
2002-01-01	2516
2002-04-01	2482
2002-07-01	2049
2002-10-01	1961
2003-01-01	2717
2003-04-01	2246
2003-07-01	2538
2003-10-01	2747
2004-01-01	1883
2004-04-01	2032
2004-07-01	3382
2004-10-01	4621
2005-01-01	7145
2005-04-01	5850
2005-07-01	5180
2005-10-01	5085
2006-01-01	5061
2006-04-01	5811
2006-07-01	6581
2006-10-01	6504
2007-01-01	7190
2007-04-01	7996
2007-07-01	7409
2007-10-01	7032
2008-01-01	8299
2008-04-01	10399
2008-07-01	11463
2008-10-01	9812
2009-01-01	8326
2009-04-01	6630
2009-07-01	7347
2009-10-01	7333
2010-01-01	7254
2010-04-01	7968
2010-07-01	9796
2010-10-01	12400
2011-01-01	14255
2011-04-01	17244
2011-07-01	17961
2011-10-01	16599
2012-01-01	17182
2012-04-01	15569
2012-07-01	16329
2012-10-01	19210
2013-01-01	21567
2013-04-01	27525
2013-07-01	37009
2013-10-01	39685
2014-01-01	41238
2014-04-01	42164
2014-07-01	43912
2014-10-01	39009
2015-01-01	33545
2015-04-01	34786
2015-07-01	29517
2015-10-01	24940
2016-01-01	27937
2016-04-01	30177
2016-07-01	35285
2016-10-01	32909
2017-01-01	35240
2017-04-01	37187
2017-07-01	34223
2017-10-01	36309
2018-01-01	40104
2018-04-01	44344