Quarter	Millions of US Dollars
1972-07-01	50
1972-10-01	50
1973-01-01	50
1973-04-01	50
1973-07-01	50
1973-10-01	50
1974-01-01	50
1974-04-01	50
1974-07-01	50
1974-10-01	50
1975-01-01	50
1975-04-01	92
1975-07-01	88
1975-10-01	88
1976-01-01	114
1976-04-01	114
1976-07-01	116
1976-10-01	117
1977-01-01	147
1977-04-01	148
1977-07-01	248
1977-10-01	300
1978-01-01	304
1978-04-01	301
1978-07-01	308
1978-10-01	315
1979-01-01	312
1979-04-01	313
1979-07-01	320
1979-10-01	321
1980-01-01	283
1980-04-01	344
1980-07-01	340
1980-10-01	332
1981-01-01	295
1981-04-01	242
1981-07-01	243
1981-10-01	244
1982-01-01	241
1982-04-01	241
1982-07-01	240
1982-10-01	242
1983-01-01	241
1983-04-01	239
1983-07-01	238
1983-10-01	237
1984-01-01	239
1984-04-01	236
1984-07-01	258
1984-10-01	296
1985-01-01	469
1985-04-01	420
1985-07-01	597
1985-10-01	529
1986-01-01	738
1986-04-01	1008
1986-07-01	1104
1986-10-01	1167
1987-01-01	1481
1987-04-01	1473
1987-07-01	1488
1987-10-01	1927
1988-01-01	2212
1988-04-01	2098
1988-07-01	2285
1988-10-01	2681
1989-01-01	2937
1989-04-01	2913
1989-07-01	3263
1989-10-01	3473
1990-01-01	3630
1990-04-01	3817
1990-07-01	4242
1990-10-01	4721
1991-01-01	4492
1991-04-01	4446
1991-07-01	4791
1991-10-01	6017
1992-01-01	6167
1992-04-01	6576
1992-07-01	7166
1992-10-01	6571
1993-01-01	7975
1993-04-01	8733
1993-07-01	10207
1993-10-01	10270
1994-01-01	11786
1994-04-01	12387
1994-07-01	13117
1994-10-01	13814
1995-01-01	15217
1995-04-01	16087
1995-07-01	15521
1995-10-01	15870
1996-01-01	15352
1996-04-01	14880
1996-07-01	14229
1996-10-01	13472
1997-01-01	12651
1997-04-01	12862
1997-07-01	12312
1997-10-01	11494
1998-01-01	10933
1998-04-01	10959
1998-07-01	11713
1998-10-01	12538
1999-01-01	11717
1999-04-01	12655
1999-07-01	12659
1999-10-01	12584
2000-01-01	11577
2000-04-01	10949
2000-07-01	10095
2000-10-01	10409
2001-01-01	9872
2001-04-01	10623
2001-07-01	11156
2001-10-01	10145
2002-01-01	9629
2002-04-01	10357
2002-07-01	10035
2002-10-01	10457
2003-01-01	11215
2003-04-01	11260
2003-07-01	11935
2003-10-01	12468
2004-01-01	11923
2004-04-01	12141
2004-07-01	13191
2004-10-01	16256
2005-01-01	18184
2005-04-01	18204
2005-07-01	18679
2005-10-01	18590
2006-01-01	22414
2006-04-01	22175
2006-07-01	24259
2006-10-01	27248
2007-01-01	30263
2007-04-01	31507
2007-07-01	33074
2007-10-01	34479
2008-01-01	38122
2008-04-01	41347
2008-07-01	38474
2008-10-01	37266
2009-01-01	33980
2009-04-01	35511
2009-07-01	38252
2009-10-01	38287
2010-01-01	37217
2010-04-01	34861
2010-07-01	36277
2010-10-01	35134
2011-01-01	39442
2011-04-01	40357
2011-07-01	38647
2011-10-01	36313
2012-01-01	36822
2012-04-01	34863
2012-07-01	35408
2012-10-01	35599
2013-01-01	36047
2013-04-01	36795
2013-07-01	38181
2013-10-01	41727
2014-01-01	43290
2014-04-01	41644
2014-07-01	36643
2014-10-01	37579
2015-01-01	34157
2015-04-01	35321
2015-07-01	35293
2015-10-01	34289
2016-01-01	34166
2016-04-01	34011
2016-07-01	32455
2016-10-01	31182
2017-01-01	31364
2017-04-01	30658
2017-07-01	29441
2017-10-01	30574
2018-01-01	28939
2018-04-01	25768