Quarter	Millions of US Dollars
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	50
1979-07-01	165
1979-10-01	166
1980-01-01	153
1980-04-01	160
1980-07-01	45
1980-10-01	99
1981-01-01	563
1981-04-01	545
1981-07-01	701
1981-10-01	664
1982-01-01	223
1982-04-01	443
1982-07-01	421
1982-10-01	678
1983-01-01	632
1983-04-01	399
1983-07-01	381
1983-10-01	253
1984-01-01	253
1984-04-01	268
1984-07-01	165
1984-10-01	305
1985-01-01	483
1985-04-01	609
1985-07-01	923
1985-10-01	1002
1986-01-01	1080
1986-04-01	952
1986-07-01	807
1986-10-01	611
1987-01-01	624
1987-04-01	857
1987-07-01	712
1987-10-01	872
1988-01-01	760
1988-04-01	757
1988-07-01	796
1988-10-01	1362
1989-01-01	1316
1989-04-01	1172
1989-07-01	1585
1989-10-01	1701
1990-01-01	1597
1990-04-01	1913
1990-07-01	1562
1990-10-01	1103
1991-01-01	1138
1991-04-01	940
1991-07-01	1921
1991-10-01	1976
1992-01-01	2005
1992-04-01	2169
1992-07-01	1605
1992-10-01	1656
1993-01-01	1904
1993-04-01	1577
1993-07-01	5547
1993-10-01	4804
1994-01-01	5065
1994-04-01	3902
1994-07-01	3136
1994-10-01	4303
1995-01-01	4650
1995-04-01	4061
1995-07-01	4582
1995-10-01	3597
1996-01-01	2359
1996-04-01	2289
1996-07-01	3289
1996-10-01	5031
1997-01-01	5653
1997-04-01	6047
1997-07-01	4983
1997-10-01	3137
1998-01-01	2168
1998-04-01	2110
1998-07-01	3026
1998-10-01	4812
1999-01-01	4851
1999-04-01	4292
1999-07-01	3594
1999-10-01	2689
2000-01-01	2737
2000-04-01	1567
2000-07-01	2349
2000-10-01	3542
2001-01-01	3373
2001-04-01	2692
2001-07-01	3375
2001-10-01	2190
2002-01-01	2644
2002-04-01	1789
2002-07-01	1557
2002-10-01	2393
2003-01-01	1786
2003-04-01	1323
2003-07-01	1621
2003-10-01	1305
2004-01-01	1158
2004-04-01	747
2004-07-01	1534
2004-10-01	1617
2005-01-01	1764
2005-04-01	2719
2005-07-01	2716
2005-10-01	2919
2006-01-01	2094
2006-04-01	1594
2006-07-01	1259
2006-10-01	1063
2007-01-01	2623
2007-04-01	2699
2007-07-01	4721
2007-10-01	5056
2008-01-01	1961
2008-04-01	1970
2008-07-01	1556
2008-10-01	3373
2009-01-01	2728
2009-04-01	3989
2009-07-01	6405
2009-10-01	5873
2010-01-01	5449
2010-04-01	5685
2010-07-01	5542
2010-10-01	4468
2011-01-01	5267
2011-04-01	8306
2011-07-01	8803
2011-10-01	8608
2012-01-01	7349
2012-04-01	4698
2012-07-01	3807
2012-10-01	7103
2013-01-01	6116
2013-04-01	3523
2013-07-01	5580
2013-10-01	6554
2014-01-01	4532
2014-04-01	2494
2014-07-01	891
2014-10-01	1030
2015-01-01	2048
2015-04-01	459
2015-07-01	311
2015-10-01	1289
2016-01-01	1739
2016-04-01	2921
2016-07-01	1295
2016-10-01	2193
2017-01-01	1427
2017-04-01	1210
2017-07-01	790
2017-10-01	1079
2018-01-01	457
2018-04-01	1705