Quarter	Millions of US Dollars
1971-10-01	0
1972-01-01	0
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	34
1977-10-01	40
1978-01-01	43
1978-04-01	43
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	0
1980-10-01	0
1981-01-01	0
1981-04-01	0
1981-07-01	0
1981-10-01	0
1982-01-01	0
1982-04-01	0
1982-07-01	0
1982-10-01	0
1983-01-01	0
1983-04-01	0
1983-07-01	12
1983-10-01	13
1984-01-01	28
1984-04-01	92
1984-07-01	129
1984-10-01	145
1985-01-01	130
1985-04-01	102
1985-07-01	102
1985-10-01	144
1986-01-01	144
1986-04-01	108
1986-07-01	58
1986-10-01	0
1987-01-01	0
1987-04-01	75
1987-07-01	99
1987-10-01	100
1988-01-01	100
1988-04-01	24
1988-07-01	0
1988-10-01	50
1989-01-01	50
1989-04-01	50
1989-07-01	50
1989-10-01	0
1990-01-01	60
1990-04-01	147
1990-07-01	152
1990-10-01	239
1991-01-01	171
1991-04-01	149
1991-07-01	179
1991-10-01	95
1992-01-01	95
1992-04-01	31
1992-07-01	0
1992-10-01	50
1993-01-01	70
1993-04-01	70
1993-07-01	695
1993-10-01	636
1994-01-01	1095
1994-04-01	1513
1994-07-01	1662
1994-10-01	1477
1995-01-01	1374
1995-04-01	1045
1995-07-01	1283
1995-10-01	1766
1996-01-01	2812
1996-04-01	2284
1996-07-01	1891
1996-10-01	2155
1997-01-01	1811
1997-04-01	2300
1997-07-01	2541
1997-10-01	2964
1998-01-01	2975
1998-04-01	3582
1998-07-01	3554
1998-10-01	3594
1999-01-01	3983
1999-04-01	3289
1999-07-01	2812
1999-10-01	2369
2000-01-01	3387
2000-04-01	3636
2000-07-01	4495
2000-10-01	5479
2001-01-01	5951
2001-04-01	6411
2001-07-01	6873
2001-10-01	5000
2002-01-01	3621
2002-04-01	4108
2002-07-01	6581
2002-10-01	7236
2003-01-01	9444
2003-04-01	9960
2003-07-01	7202
2003-10-01	6537
2004-01-01	3951
2004-04-01	3099
2004-07-01	1955
2004-10-01	2181
2005-01-01	4322
2005-04-01	4320
2005-07-01	4904
2005-10-01	4758
2006-01-01	3814
2006-04-01	4150
2006-07-01	5359
2006-10-01	5662
2007-01-01	5477
2007-04-01	5035
2007-07-01	3634
2007-10-01	4271
2008-01-01	5725
2008-04-01	6839
2008-07-01	7558
2008-10-01	7900
2009-01-01	6910
2009-04-01	6467
2009-07-01	5959
2009-10-01	7534
2010-01-01	10840
2010-04-01	11127
2010-07-01	12887
2010-10-01	12839
2011-01-01	10546
2011-04-01	12472
2011-07-01	11277
2011-10-01	8668
2012-01-01	12599
2012-04-01	13142
2012-07-01	14674
2012-10-01	14980
2013-01-01	13395
2013-04-01	15671
2013-07-01	15443
2013-10-01	15717
2014-01-01	16700
2014-04-01	17389
2014-07-01	17910
2014-10-01	19393
2015-01-01	20690
2015-04-01	16382
2015-07-01	12571
2015-10-01	14616
2016-01-01	21415
2016-04-01	27877
2016-07-01	29446
2016-10-01	28652
2017-01-01	24298
2017-04-01	20984
2017-07-01	20930
2017-10-01	19470
2018-01-01	20320
2018-04-01	23123