Quarter	Millions of US Dollars
1972-01-01	20
1972-04-01	40
1972-07-01	40
1972-10-01	40
1973-01-01	40
1973-04-01	40
1973-07-01	40
1973-10-01	40
1974-01-01	40
1974-04-01	40
1974-07-01	49
1974-10-01	49
1975-01-01	49
1975-04-01	49
1975-07-01	49
1975-10-01	49
1976-01-01	49
1976-04-01	49
1976-07-01	49
1976-10-01	63
1977-01-01	63
1977-04-01	65
1977-07-01	90
1977-10-01	90
1978-01-01	184
1978-04-01	188
1978-07-01	262
1978-10-01	303
1979-01-01	375
1979-04-01	372
1979-07-01	369
1979-10-01	363
1980-01-01	358
1980-04-01	353
1980-07-01	381
1980-10-01	385
1981-01-01	380
1981-04-01	372
1981-07-01	369
1981-10-01	374
1982-01-01	348
1982-04-01	345
1982-07-01	316
1982-10-01	328
1983-01-01	317
1983-04-01	316
1983-07-01	318
1983-10-01	320
1984-01-01	304
1984-04-01	297
1984-07-01	293
1984-10-01	290
1985-01-01	290
1985-04-01	291
1985-07-01	308
1985-10-01	263
1986-01-01	259
1986-04-01	273
1986-07-01	283
1986-10-01	264
1987-01-01	280
1987-04-01	278
1987-07-01	252
1987-10-01	291
1988-01-01	192
1988-04-01	182
1988-07-01	180
1988-10-01	190
1989-01-01	182
1989-04-01	172
1989-07-01	175
1989-10-01	172
1990-01-01	161
1990-04-01	165
1990-07-01	152
1990-10-01	136
1991-01-01	132
1991-04-01	134
1991-07-01	139
1991-10-01	147
1992-01-01	139
1992-04-01	146
1992-07-01	153
1992-10-01	147
1993-01-01	115
1993-04-01	125
1993-07-01	125
1993-10-01	118
1994-01-01	11
1994-04-01	11
1994-07-01	11
1994-10-01	11
1995-01-01	11
1995-04-01	11
1995-07-01	11
1995-10-01	11
1996-01-01	13
1996-04-01	18
1996-07-01	3242
1996-10-01	3240
1997-01-01	3734
1997-04-01	3742
1997-07-01	4557
1997-10-01	4550
1998-01-01	4549
1998-04-01	4849
1998-07-01	4849
1998-10-01	4235
1999-01-01	4735
1999-04-01	4735
1999-07-01	4735
1999-10-01	4735
2000-01-01	4735
2000-04-01	4709
2000-07-01	5059
2000-10-01	5059
2001-01-01	6074
2001-04-01	5918
2001-07-01	5895
2001-10-01	5531
2002-01-01	5181
2002-04-01	5219
2002-07-01	5312
2002-10-01	5359
2003-01-01	5540
2003-04-01	5554
2003-07-01	5514
2003-10-01	5543
2004-01-01	5709
2004-04-01	5683
2004-07-01	5682
2004-10-01	6318
2005-01-01	6298
2005-04-01	6272
2005-07-01	6671
2005-10-01	7774
2006-01-01	8783
2006-04-01	8173
2006-07-01	8127
2006-10-01	8127
2007-01-01	8127
2007-04-01	8577
2007-07-01	8577
2007-10-01	8897
2008-01-01	8897
2008-04-01	8567
2008-07-01	8567
2008-10-01	8567
2009-01-01	8890
2009-04-01	8890
2009-07-01	8890
2009-10-01	9890
2010-01-01	9890
2010-04-01	9890
2010-07-01	9890
2010-10-01	9740
2011-01-01	9819
2011-04-01	9833
2011-07-01	10572
2011-10-01	10568
2012-01-01	10388
2012-04-01	10404
2012-07-01	10137
2012-10-01	11584
2013-01-01	11542
2013-04-01	12272
2013-07-01	12378
2013-10-01	12678
2014-01-01	12684
2014-04-01	13063
2014-07-01	14255
2014-10-01	14393
2015-01-01	14302
2015-04-01	14460
2015-07-01	14450
2015-10-01	14893
2016-01-01	15930
2016-04-01	16883
2016-07-01	16890
2016-10-01	17370
2017-01-01	17542
2017-04-01	18979
2017-07-01	20018
2017-10-01	19519
2018-01-01	19551
2018-04-01	20771