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	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	24
1981-04-01	21
1981-07-01	21
1981-10-01	22
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	0
1983-10-01	0
1984-01-01	0
1984-04-01	63
1984-07-01	113
1984-10-01	416
1985-01-01	429
1985-04-01	376
1985-07-01	455
1985-10-01	175
1986-01-01	183
1986-04-01	185
1986-07-01	102
1986-10-01	60
1987-01-01	67
1987-04-01	53
1987-07-01	27
1987-10-01	31
1988-01-01	22
1988-04-01	21
1988-07-01	20
1988-10-01	65
1989-01-01	53
1989-04-01	53
1989-07-01	153
1989-10-01	123
1990-01-01	120
1990-04-01	120
1990-07-01	121
1990-10-01	100
1991-01-01	102
1991-04-01	177
1991-07-01	77
1991-10-01	77
1992-01-01	75
1992-04-01	40
1992-07-01	40
1992-10-01	40
1993-01-01	40
1993-04-01	60
1993-07-01	300
1993-10-01	329
1994-01-01	301
1994-04-01	343
1994-07-01	370
1994-10-01	752
1995-01-01	740
1995-04-01	549
1995-07-01	441
1995-10-01	939
1996-01-01	1320
1996-04-01	1331
1996-07-01	1121
1996-10-01	703
1997-01-01	808
1997-04-01	1124
1997-07-01	694
1997-10-01	665
1998-01-01	404
1998-04-01	150
1998-07-01	338
1998-10-01	1734
1999-01-01	1877
1999-04-01	1813
1999-07-01	2441
1999-10-01	1110
2000-01-01	2108
2000-04-01	2125
2000-07-01	944
2000-10-01	2100
2001-01-01	3184
2001-04-01	3234
2001-07-01	3865
2001-10-01	4783
2002-01-01	3231
2002-04-01	4373
2002-07-01	5252
2002-10-01	3076
2003-01-01	3065
2003-04-01	2999
2003-07-01	1894
2003-10-01	2127
2004-01-01	1648
2004-04-01	1854
2004-07-01	2034
2004-10-01	1931
2005-01-01	2565
2005-04-01	1875
2005-07-01	1408
2005-10-01	3587
2006-01-01	3796
2006-04-01	4275
2006-07-01	5394
2006-10-01	4631
2007-01-01	5755
2007-04-01	5971
2007-07-01	4845
2007-10-01	4167
2008-01-01	2765
2008-04-01	1874
2008-07-01	1899
2008-10-01	2475
2009-01-01	2704
2009-04-01	3138
2009-07-01	3093
2009-10-01	3244
2010-01-01	2823
2010-04-01	3659
2010-07-01	5520
2010-10-01	5019
2011-01-01	6557
2011-04-01	10968
2011-07-01	9177
2011-10-01	10661
2012-01-01	8396
2012-04-01	7236
2012-07-01	6795
2012-10-01	6454
2013-01-01	4258
2013-04-01	9219
2013-07-01	12063
2013-10-01	11473
2014-01-01	13508
2014-04-01	7829
2014-07-01	6623
2014-10-01	7865
2015-01-01	7899
2015-04-01	12637
2015-07-01	12749
2015-10-01	14067
2016-01-01	21280
2016-04-01	20484
2016-07-01	19705
2016-10-01	18345
2017-01-01	14178
2017-04-01	11824
2017-07-01	13042
2017-10-01	11951
2018-01-01	14518
2018-04-01	13640