Quarter	Millions of US Dollars
1970-10-01	0
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	4
1976-07-01	4
1976-10-01	4
1977-01-01	82
1977-04-01	81
1977-07-01	96
1977-10-01	137
1978-01-01	112
1978-04-01	178
1978-07-01	246
1978-10-01	216
1979-01-01	174
1979-04-01	204
1979-07-01	184
1979-10-01	369
1980-01-01	389
1980-04-01	433
1980-07-01	472
1980-10-01	447
1981-01-01	385
1981-04-01	420
1981-07-01	392
1981-10-01	235
1982-01-01	289
1982-04-01	249
1982-07-01	246
1982-10-01	297
1983-01-01	502
1983-04-01	472
1983-07-01	418
1983-10-01	552
1984-01-01	611
1984-04-01	664
1984-07-01	856
1984-10-01	1400
1985-01-01	1239
1985-04-01	1315
1985-07-01	1165
1985-10-01	643
1986-01-01	740
1986-04-01	679
1986-07-01	675
1986-10-01	1163
1987-01-01	1284
1987-04-01	1573
1987-07-01	1757
1987-10-01	4026
1988-01-01	3877
1988-04-01	4784
1988-07-01	4672
1988-10-01	2674
1989-01-01	3038
1989-04-01	2587
1989-07-01	3003
1989-10-01	3687
1990-01-01	3606
1990-04-01	3388
1990-07-01	3301
1990-10-01	3279
1991-01-01	3186
1991-04-01	3449
1991-07-01	4241
1991-10-01	4608
1992-01-01	7140
1992-04-01	8761
1992-07-01	10406
1992-10-01	10186
1993-01-01	11450
1993-04-01	11926
1993-07-01	26895
1993-10-01	32098
1994-01-01	32985
1994-04-01	37138
1994-07-01	44665
1994-10-01	44686
1995-01-01	53419
1995-04-01	58796
1995-07-01	63711
1995-10-01	67425
1996-01-01	66227
1996-04-01	72020
1996-07-01	49115
1996-10-01	88453
1997-01-01	84498
1997-04-01	86233
1997-07-01	90908
1997-10-01	89387
1998-01-01	94658
1998-04-01	95203
1998-07-01	101278
1998-10-01	98692
1999-01-01	105331
1999-04-01	108845
1999-07-01	132962
1999-10-01	137432
2000-01-01	153410
2000-04-01	174663
2000-07-01	171676
2000-10-01	188619
2001-01-01	186447
2001-04-01	172670
2001-07-01	167583
2001-10-01	168971
2002-01-01	168269
2002-04-01	182544
2002-07-01	203822
2002-10-01	200986
2003-01-01	234157
2003-04-01	253536
2003-07-01	263619
2003-10-01	299778
2004-01-01	294347
2004-04-01	320985
2004-07-01	335852
2004-10-01	362445
2005-01-01	359862
2005-04-01	367967
2005-07-01	404698
2005-10-01	430701
2006-01-01	458291
2006-04-01	487467
2006-07-01	511973
2006-10-01	540027
2007-01-01	576304
2007-04-01	564386
2007-07-01	626340
2007-10-01	618821
2008-01-01	732947
2008-04-01	770985
2008-07-01	684129
2008-10-01	661799
2009-01-01	603112
2009-04-01	598809
2009-07-01	610273
2009-10-01	562571
2010-01-01	575009
2010-04-01	532844
2010-07-01	593408
2010-10-01	569273
2011-01-01	651729
2011-04-01	702602
2011-07-01	674700
2011-10-01	588902
2012-01-01	576322
2012-04-01	505640
2012-07-01	507093
2012-10-01	500852
2013-01-01	487431
2013-04-01	476823
2013-07-01	490174
2013-10-01	498197
2014-01-01	509120
2014-04-01	515658
2014-07-01	510907
2014-10-01	513884
2015-01-01	469883
2015-04-01	467251
2015-07-01	453303
2015-10-01	413886
2016-01-01	444830
2016-04-01	444322
2016-07-01	432484
2016-10-01	435968
2017-01-01	434434
2017-04-01	428816
2017-07-01	420428
2017-10-01	449697
2018-01-01	451917
2018-04-01	452948