Quarter	Millions of US Dollars
1971-01-01	0
1971-04-01	0
1971-07-01	0
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	0
1977-10-01	0
1978-01-01	0
1978-04-01	0
1978-07-01	0
1978-10-01	25
1979-01-01	25
1979-04-01	40
1979-07-01	51
1979-10-01	51
1980-01-01	88
1980-04-01	78
1980-07-01	66
1980-10-01	38
1981-01-01	72
1981-04-01	100
1981-07-01	103
1981-10-01	107
1982-01-01	37
1982-04-01	0
1982-07-01	0
1982-10-01	100
1983-01-01	100
1983-04-01	148
1983-07-01	147
1983-10-01	70
1984-01-01	70
1984-04-01	159
1984-07-01	213
1984-10-01	631
1985-01-01	732
1985-04-01	660
1985-07-01	657
1985-10-01	298
1986-01-01	321
1986-04-01	385
1986-07-01	514
1986-10-01	525
1987-01-01	476
1987-04-01	438
1987-07-01	302
1987-10-01	349
1988-01-01	473
1988-04-01	512
1988-07-01	537
1988-10-01	471
1989-01-01	334
1989-04-01	375
1989-07-01	432
1989-10-01	470
1990-01-01	513
1990-04-01	495
1990-07-01	396
1990-10-01	430
1991-01-01	327
1991-04-01	155
1991-07-01	169
1991-10-01	216
1992-01-01	152
1992-04-01	200
1992-07-01	289
1992-10-01	96
1993-01-01	95
1993-04-01	359
1993-07-01	452
1993-10-01	635
1994-01-01	694
1994-04-01	441
1994-07-01	495
1994-10-01	318
1995-01-01	323
1995-04-01	245
1995-07-01	245
1995-10-01	581
1996-01-01	893
1996-04-01	881
1996-07-01	640
1996-10-01	573
1997-01-01	259
1997-04-01	310
1997-07-01	310
1997-10-01	232
1998-01-01	342
1998-04-01	309
1998-07-01	317
1998-10-01	888
1999-01-01	829
1999-04-01	1287
1999-07-01	1299
1999-10-01	461
2000-01-01	481
2000-04-01	161
2000-07-01	155
2000-10-01	349
2001-01-01	610
2001-04-01	543
2001-07-01	654
2001-10-01	1048
2002-01-01	821
2002-04-01	849
2002-07-01	622
2002-10-01	1482
2003-01-01	1497
2003-04-01	2005
2003-07-01	2045
2003-10-01	975
2004-01-01	968
2004-04-01	412
2004-07-01	419
2004-10-01	222
2005-01-01	410
2005-04-01	1710
2005-07-01	2203
2005-10-01	3721
2006-01-01	3849
2006-04-01	2622
2006-07-01	2800
2006-10-01	1543
2007-01-01	1278
2007-04-01	1839
2007-07-01	1793
2007-10-01	1342
2008-01-01	2073
2008-04-01	3778
2008-07-01	3089
2008-10-01	3115
2009-01-01	3258
2009-04-01	1609
2009-07-01	1613
2009-10-01	1572
2010-01-01	877
2010-04-01	26
2010-07-01	1026
2010-10-01	1056
2011-01-01	1180
2011-04-01	2380
2011-07-01	3792
2011-10-01	4751
2012-01-01	3630
2012-04-01	6520
2012-07-01	4170
2012-10-01	4203
2013-01-01	4655
2013-04-01	6534
2013-07-01	6534
2013-10-01	9434
2014-01-01	12434
2014-04-01	6984
2014-07-01	8234
2014-10-01	7494
2015-01-01	3890
2015-04-01	4212
2015-07-01	3969
2015-10-01	2855
2016-01-01	4896
2016-04-01	4738
2016-07-01	3741
2016-10-01	5820
2017-01-01	5828
2017-04-01	5153
2017-07-01	5632
2017-10-01	2522
2018-01-01	2000
2018-04-01	9696