Quarter	Millions of US Dollars
1971-01-01	15
1971-04-01	15
1971-07-01	15
1971-10-01	63
1972-01-01	143
1972-04-01	175
1972-07-01	294
1972-10-01	361
1973-01-01	458
1973-04-01	506
1973-07-01	572
1973-10-01	540
1974-01-01	589
1974-04-01	590
1974-07-01	586
1974-10-01	680
1975-01-01	834
1975-04-01	862
1975-07-01	958
1975-10-01	1056
1976-01-01	1134
1976-04-01	1169
1976-07-01	1256
1976-10-01	1451
1977-01-01	1493
1977-04-01	1621
1977-07-01	1720
1977-10-01	2029
1978-01-01	2436
1978-04-01	2738
1978-07-01	3097
1978-10-01	3354
1979-01-01	3546
1979-04-01	3695
1979-07-01	3839
1979-10-01	3964
1980-01-01	3684
1980-04-01	4045
1980-07-01	3988
1980-10-01	3852
1981-01-01	3704
1981-04-01	3726
1981-07-01	3776
1981-10-01	4122
1982-01-01	3992
1982-04-01	4100
1982-07-01	4194
1982-10-01	4564
1983-01-01	4598
1983-04-01	4725
1983-07-01	4813
1983-10-01	4738
1984-01-01	5120
1984-04-01	5191
1984-07-01	5235
1984-10-01	5362
1985-01-01	5678
1985-04-01	5878
1985-07-01	6466
1985-10-01	6565
1986-01-01	7359
1986-04-01	8116
1986-07-01	9118
1986-10-01	9811
1987-01-01	12489
1987-04-01	13252
1987-07-01	13966
1987-10-01	15972
1988-01-01	16420
1988-04-01	16827
1988-07-01	17595
1988-10-01	18596
1989-01-01	20142
1989-04-01	19673
1989-07-01	20845
1989-10-01	21597
1990-01-01	22873
1990-04-01	25700
1990-07-01	28766
1990-10-01	30130
1991-01-01	30703
1991-04-01	30843
1991-07-01	33232
1991-10-01	35349
1992-01-01	35195
1992-04-01	41003
1992-07-01	44192
1992-10-01	44176
1993-01-01	46719
1993-04-01	48865
1993-07-01	48819
1993-10-01	46383
1994-01-01	49205
1994-04-01	52084
1994-07-01	57128
1994-10-01	56442
1995-01-01	61141
1995-04-01	60256
1995-07-01	57895
1995-10-01	55475
1996-01-01	55446
1996-04-01	53305
1996-07-01	51887
1996-10-01	52659
1997-01-01	51331
1997-04-01	50521
1997-07-01	48298
1997-10-01	45755
1998-01-01	42493
1998-04-01	42386
1998-07-01	43695
1998-10-01	42484
1999-01-01	39403
1999-04-01	39177
1999-07-01	42512
1999-10-01	40536
2000-01-01	37497
2000-04-01	38202
2000-07-01	35322
2000-10-01	35136
2001-01-01	32881
2001-04-01	37254
2001-07-01	37928
2001-10-01	36487
2002-01-01	37351
2002-04-01	39478
2002-07-01	38577
2002-10-01	41774
2003-01-01	49680
2003-04-01	54475
2003-07-01	57748
2003-10-01	61681
2004-01-01	64732
2004-04-01	66582
2004-07-01	64761
2004-10-01	74959
2005-01-01	70837
2005-04-01	67213
2005-07-01	69111
2005-10-01	70164
2006-01-01	75362
2006-04-01	81682
2006-07-01	73735
2006-10-01	76202
2007-01-01	75411
2007-04-01	78847
2007-07-01	74221
2007-10-01	73059
2008-01-01	74784
2008-04-01	77783
2008-07-01	68062
2008-10-01	67048
2009-01-01	70879
2009-04-01	77593
2009-07-01	82843
2009-10-01	83809
2010-01-01	83683
2010-04-01	78201
2010-07-01	87195
2010-10-01	94697
2011-01-01	112335
2011-04-01	119513
2011-07-01	115954
2011-10-01	113966
2012-01-01	127574
2012-04-01	133064
2012-07-01	137585
2012-10-01	139413
2013-01-01	141778
2013-04-01	147259
2013-07-01	156175
2013-10-01	163012
2014-01-01	169609
2014-04-01	175751
2014-07-01	167996
2014-10-01	165238
2015-01-01	156294
2015-04-01	166548
2015-07-01	170131
2015-10-01	163880
2016-01-01	166583
2016-04-01	168473
2016-07-01	168705
2016-10-01	163610
2017-01-01	170347
2017-04-01	178205
2017-07-01	185173
2017-10-01	190872
2018-01-01	202484
2018-04-01	192907