Quarter	Millions of US Dollars
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	25
1979-04-01	25
1979-07-01	25
1979-10-01	25
1980-01-01	30
1980-04-01	166
1980-07-01	164
1980-10-01	194
1981-01-01	161
1981-04-01	35
1981-07-01	70
1981-10-01	58
1982-01-01	116
1982-04-01	174
1982-07-01	175
1982-10-01	172
1983-01-01	112
1983-04-01	123
1983-07-01	89
1983-10-01	114
1984-01-01	115
1984-04-01	93
1984-07-01	192
1984-10-01	258
1985-01-01	278
1985-04-01	251
1985-07-01	157
1985-10-01	74
1986-01-01	55
1986-04-01	63
1986-07-01	67
1986-10-01	40
1987-01-01	41
1987-04-01	16
1987-07-01	12
1987-10-01	11
1988-01-01	38
1988-04-01	55
1988-07-01	134
1988-10-01	133
1989-01-01	103
1989-04-01	147
1989-07-01	94
1989-10-01	92
1990-01-01	86
1990-04-01	23
1990-07-01	0
1990-10-01	111
1991-01-01	268
1991-04-01	282
1991-07-01	296
1991-10-01	440
1992-01-01	605
1992-04-01	768
1992-07-01	793
1992-10-01	789
1993-01-01	851
1993-04-01	742
1993-07-01	979
1993-10-01	964
1994-01-01	1545
1994-04-01	2016
1994-07-01	2610
1994-10-01	3340
1995-01-01	3006
1995-04-01	3707
1995-07-01	5154
1995-10-01	5321
1996-01-01	5795
1996-04-01	4946
1996-07-01	3003
1996-10-01	2794
1997-01-01	2713
1997-04-01	3348
1997-07-01	4213
1997-10-01	6713
1998-01-01	5896
1998-04-01	7336
1998-07-01	7593
1998-10-01	5609
1999-01-01	7072
1999-04-01	5460
1999-07-01	6219
1999-10-01	6945
2000-01-01	5269
2000-04-01	6341
2000-07-01	4580
2000-10-01	6719
2001-01-01	6710
2001-04-01	8611
2001-07-01	9109
2001-10-01	9321
2002-01-01	9144
2002-04-01	10307
2002-07-01	11289
2002-10-01	9873
2003-01-01	13182
2003-04-01	9791
2003-07-01	9969
2003-10-01	10420
2004-01-01	9300
2004-04-01	9218
2004-07-01	13371
2004-10-01	15850
2005-01-01	11848
2005-04-01	13094
2005-07-01	9037
2005-10-01	11281
2006-01-01	11500
2006-04-01	14201
2006-07-01	14258
2006-10-01	11324
2007-01-01	14972
2007-04-01	11341
2007-07-01	10734
2007-10-01	10749
2008-01-01	12237
2008-04-01	14717
2008-07-01	19342
2008-10-01	20616
2009-01-01	22582
2009-04-01	23679
2009-07-01	23910
2009-10-01	22852
2010-01-01	20426
2010-04-01	18454
2010-07-01	19843
2010-10-01	24773
2011-01-01	23071
2011-04-01	24567
2011-07-01	22989
2011-10-01	19650
2012-01-01	29196
2012-04-01	25660
2012-07-01	25125
2012-10-01	23971
2013-01-01	34427
2013-04-01	40192
2013-07-01	45751
2013-10-01	45447
2014-01-01	30010
2014-04-01	30237
2014-07-01	31884
2014-10-01	53757
2015-01-01	54002
2015-04-01	53973
2015-07-01	52427
2015-10-01	29693
2016-01-01	29758
2016-04-01	35707
2016-07-01	36366
2016-10-01	38425
2017-01-01	42061
2017-04-01	52085
2017-07-01	53023
2017-10-01	58610
2018-01-01	57437
2018-04-01	50324