Quarter	Millions of US Dollars
1972-01-01	20
1972-04-01	60
1972-07-01	60
1972-10-01	60
1973-01-01	62
1973-04-01	64
1973-07-01	64
1973-10-01	61
1974-01-01	61
1974-04-01	61
1974-07-01	70
1974-10-01	71
1975-01-01	73
1975-04-01	74
1975-07-01	71
1975-10-01	71
1976-01-01	70
1976-04-01	70
1976-07-01	69
1976-10-01	83
1977-01-01	83
1977-04-01	85
1977-07-01	110
1977-10-01	112
1978-01-01	205
1978-04-01	210
1978-07-01	285
1978-10-01	327
1979-01-01	399
1979-04-01	395
1979-07-01	508
1979-10-01	503
1980-01-01	496
1980-04-01	613
1980-07-01	640
1980-10-01	642
1981-01-01	636
1981-04-01	624
1981-07-01	621
1981-10-01	627
1982-01-01	599
1982-04-01	595
1982-07-01	565
1982-10-01	578
1983-01-01	565
1983-04-01	664
1983-07-01	666
1983-10-01	667
1984-01-01	651
1984-04-01	644
1984-07-01	639
1984-10-01	735
1985-01-01	736
1985-04-01	736
1985-07-01	792
1985-10-01	707
1986-01-01	709
1986-04-01	729
1986-07-01	748
1986-10-01	769
1987-01-01	900
1987-04-01	1017
1987-07-01	989
1987-10-01	1066
1988-01-01	958
1988-04-01	935
1988-07-01	925
1988-10-01	960
1989-01-01	930
1989-04-01	846
1989-07-01	790
1989-10-01	811
1990-01-01	796
1990-04-01	807
1990-07-01	750
1990-10-01	617
1991-01-01	587
1991-04-01	579
1991-07-01	602
1991-10-01	624
1992-01-01	498
1992-04-01	442
1992-07-01	466
1992-10-01	433
1993-01-01	401
1993-04-01	402
1993-07-01	410
1993-10-01	305
1994-01-01	201
1994-04-01	205
1994-07-01	208
1994-10-01	238
1995-01-01	249
1995-04-01	249
1995-07-01	246
1995-10-01	131
1996-01-01	173
1996-04-01	218
1996-07-01	3503
1996-10-01	3415
1997-01-01	3809
1997-04-01	3817
1997-07-01	4632
1997-10-01	4756
1998-01-01	4755
1998-04-01	5055
1998-07-01	4980
1998-10-01	4366
1999-01-01	4866
1999-04-01	4862
1999-07-01	4861
1999-10-01	4856
2000-01-01	4856
2000-04-01	4826
2000-07-01	5176
2000-10-01	5171
2001-01-01	6186
2001-04-01	6026
2001-07-01	6002
2001-10-01	5634
2002-01-01	5284
2002-04-01	5317
2002-07-01	5410
2002-10-01	5453
2003-01-01	5633
2003-04-01	5643
2003-07-01	5617
2003-10-01	5642
2004-01-01	5817
2004-04-01	5785
2004-07-01	5773
2004-10-01	6405
2005-01-01	6377
2005-04-01	6346
2005-07-01	6741
2005-10-01	7839
2006-01-01	9149
2006-04-01	8538
2006-07-01	8592
2006-10-01	8883
2007-01-01	8883
2007-04-01	9328
2007-07-01	9328
2007-10-01	9805
2008-01-01	9820
2008-04-01	9437
2008-07-01	9436
2008-10-01	9423
2009-01-01	9745
2009-04-01	9748
2009-07-01	9755
2009-10-01	10755
2010-01-01	10758
2010-04-01	10856
2010-07-01	10888
2010-10-01	10749
2011-01-01	10807
2011-04-01	11069
2011-07-01	11910
2011-10-01	12193
2012-01-01	12026
2012-04-01	12411
2012-07-01	12147
2012-10-01	13159
2013-01-01	13432
2013-04-01	14664
2013-07-01	14748
2013-10-01	14999
2014-01-01	15192
2014-04-01	16759
2014-07-01	17951
2014-10-01	17676
2015-01-01	17573
2015-04-01	18031
2015-07-01	18081
2015-10-01	18494
2016-01-01	19201
2016-04-01	19802
2016-07-01	19785
2016-10-01	20102
2017-01-01	20340
2017-04-01	21490
2017-07-01	22572
2017-10-01	22680
2018-01-01	22643
2018-04-01	24565