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	44
1979-01-01	43
1979-04-01	43
1979-07-01	44
1979-10-01	58
1980-01-01	51
1980-04-01	57
1980-07-01	146
1980-10-01	85
1981-01-01	78
1981-04-01	100
1981-07-01	27
1981-10-01	27
1982-01-01	25
1982-04-01	0
1982-07-01	23
1982-10-01	25
1983-01-01	24
1983-04-01	132
1983-07-01	107
1983-10-01	103
1984-01-01	106
1984-04-01	0
1984-07-01	20
1984-10-01	197
1985-01-01	219
1985-04-01	221
1985-07-01	215
1985-10-01	166
1986-01-01	468
1986-04-01	544
1986-07-01	679
1986-10-01	842
1987-01-01	838
1987-04-01	790
1987-07-01	1083
1987-10-01	856
1988-01-01	1076
1988-04-01	1019
1988-07-01	598
1988-10-01	703
1989-01-01	288
1989-04-01	271
1989-07-01	605
1989-10-01	489
1990-01-01	443
1990-04-01	449
1990-07-01	192
1990-10-01	479
1991-01-01	332
1991-04-01	756
1991-07-01	756
1991-10-01	545
1992-01-01	530
1992-04-01	366
1992-07-01	337
1992-10-01	691
1993-01-01	1302
1993-04-01	1046
1993-07-01	1344
1993-10-01	1510
1994-01-01	1482
1994-04-01	1457
1994-07-01	1269
1994-10-01	892
1995-01-01	1772
1995-04-01	1810
1995-07-01	1784
1995-10-01	1546
1996-01-01	926
1996-04-01	987
1996-07-01	868
1996-10-01	1245
1997-01-01	902
1997-04-01	725
1997-07-01	705
1997-10-01	485
1998-01-01	925
1998-04-01	1096
1998-07-01	1172
1998-10-01	1008
1999-01-01	1590
1999-04-01	1565
1999-07-01	801
1999-10-01	1648
2000-01-01	1989
2000-04-01	3094
2000-07-01	964
2000-10-01	1384
2001-01-01	952
2001-04-01	400
2001-07-01	2396
2001-10-01	6175
2002-01-01	6540
2002-04-01	6381
2002-07-01	5213
2002-10-01	6059
2003-01-01	5578
2003-04-01	6546
2003-07-01	4497
2003-10-01	2913
2004-01-01	2761
2004-04-01	1545
2004-07-01	897
2004-10-01	715
2005-01-01	148
2005-04-01	0
2005-07-01	0
2005-10-01	0
2006-01-01	5
2006-04-01	0
2006-07-01	0
2006-10-01	0
2007-01-01	0
2007-04-01	967
2007-07-01	12256
2007-10-01	1078
2008-01-01	7386
2008-04-01	7876
2008-07-01	17386
2008-10-01	27632
2009-01-01	22834
2009-04-01	19425
2009-07-01	10681
2009-10-01	4344
2010-01-01	2488
2010-04-01	3223
2010-07-01	5840
2010-10-01	1042
2011-01-01	744
2011-04-01	675
2011-07-01	734
2011-10-01	452
2012-01-01	1146
2012-04-01	1410
2012-07-01	1604
2012-10-01	1720
2013-01-01	1850
2013-04-01	2312
2013-07-01	991
2013-10-01	670
2014-01-01	801
2014-04-01	572
2014-07-01	1909
2014-10-01	2823
2015-01-01	3564
2015-04-01	2928
2015-07-01	2750
2015-10-01	1148
2016-01-01	2586
2016-04-01	1844
2016-07-01	2825
2016-10-01	3020
2017-01-01	4525
2017-04-01	6077
2017-07-01	5094
2017-10-01	608
2018-01-01	3659
2018-04-01	3691