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	274
1989-07-01	206
1989-10-01	7
1990-01-01	0
1990-04-01	0
1990-07-01	60
1990-10-01	60
1991-01-01	110
1991-04-01	160
1991-07-01	100
1991-10-01	175
1992-01-01	125
1992-04-01	75
1992-07-01	75
1992-10-01	0
1993-01-01	0
1993-04-01	0
1993-07-01	214
1993-10-01	165
1994-01-01	288
1994-04-01	260
1994-07-01	260
1994-10-01	261
1995-01-01	242
1995-04-01	242
1995-07-01	444
1995-10-01	444
1996-01-01	721
1996-04-01	908
1996-07-01	871
1996-10-01	819
1997-01-01	650
1997-04-01	585
1997-07-01	385
1997-10-01	288
1998-01-01	200
1998-04-01	815
1998-07-01	967
1998-10-01	1082
1999-01-01	1098
1999-04-01	538
1999-07-01	1012
1999-10-01	954
2000-01-01	1029
2000-04-01	2027
2000-07-01	1690
2000-10-01	2699
2001-01-01	2653
2001-04-01	3666
2001-07-01	3921
2001-10-01	2734
2002-01-01	2616
2002-04-01	1342
2002-07-01	782
2002-10-01	782
2003-01-01	1603
2003-04-01	1265
2003-07-01	1924
2003-10-01	2369
2004-01-01	1767
2004-04-01	1966
2004-07-01	2057
2004-10-01	3548
2005-01-01	3674
2005-04-01	3195
2005-07-01	3273
2005-10-01	2592
2006-01-01	3486
2006-04-01	4419
2006-07-01	4245
2006-10-01	4336
2007-01-01	2889
2007-04-01	3653
2007-07-01	4072
2007-10-01	4109
2008-01-01	5393
2008-04-01	7892
2008-07-01	8010
2008-10-01	7295
2009-01-01	5786
2009-04-01	4922
2009-07-01	5934
2009-10-01	5751
2010-01-01	6616
2010-04-01	6236
2010-07-01	7804
2010-10-01	9993
2011-01-01	11014
2011-04-01	14545
2011-07-01	15885
2011-10-01	15280
2012-01-01	15350
2012-04-01	13634
2012-07-01	13363
2012-10-01	15537
2013-01-01	17379
2013-04-01	20303
2013-07-01	25058
2013-10-01	29096
2014-01-01	28935
2014-04-01	30566
2014-07-01	32740
2014-10-01	27513
2015-01-01	24036
2015-04-01	25444
2015-07-01	21337
2015-10-01	18945
2016-01-01	21182
2016-04-01	18438
2016-07-01	18844
2016-10-01	15346
2017-01-01	17712
2017-04-01	19038
2017-07-01	20458
2017-10-01	20267
2018-01-01	27170
2018-04-01	28974