Quarter	Millions of US Dollars
1971-01-01	88
1971-04-01	141
1971-07-01	169
1971-10-01	251
1972-01-01	508
1972-04-01	664
1972-07-01	879
1972-10-01	1295
1973-01-01	1507
1973-04-01	1999
1973-07-01	2134
1973-10-01	2590
1974-01-01	2771
1974-04-01	3252
1974-07-01	3291
1974-10-01	3544
1975-01-01	3930
1975-04-01	4484
1975-07-01	4529
1975-10-01	4757
1976-01-01	4994
1976-04-01	5462
1976-07-01	6161
1976-10-01	6796
1977-01-01	7473
1977-04-01	8393
1977-07-01	9700
1977-10-01	11406
1978-01-01	13424
1978-04-01	14840
1978-07-01	16392
1978-10-01	17728
1979-01-01	18356
1979-04-01	19030
1979-07-01	20292
1979-10-01	20377
1980-01-01	19264
1980-04-01	21065
1980-07-01	21527
1980-10-01	21262
1981-01-01	20784
1981-04-01	20419
1981-07-01	21092
1981-10-01	22579
1982-01-01	22753
1982-04-01	22644
1982-07-01	22250
1982-10-01	23559
1983-01-01	22987
1983-04-01	22812
1983-07-01	23953
1983-10-01	23699
1984-01-01	24365
1984-04-01	23764
1984-07-01	23369
1984-10-01	24373
1985-01-01	25338
1985-04-01	27516
1985-07-01	29795
1985-10-01	30591
1986-01-01	32841
1986-04-01	34414
1986-07-01	35632
1986-10-01	35074
1987-01-01	38238
1987-04-01	37556
1987-07-01	37279
1987-10-01	40700
1988-01-01	40593
1988-04-01	38182
1988-07-01	38036
1988-10-01	40530
1989-01-01	39508
1989-04-01	38150
1989-07-01	40652
1989-10-01	41637
1990-01-01	76948
1990-04-01	78157
1990-07-01	81872
1990-10-01	100181
1991-01-01	98457
1991-04-01	101919
1991-07-01	105524
1991-10-01	113802
1992-01-01	116482
1992-04-01	122368
1992-07-01	129918
1992-10-01	133060
1993-01-01	139153
1993-04-01	164351
1993-07-01	176770
1993-10-01	198175
1994-01-01	214107
1994-04-01	262911
1994-07-01	276700
1994-10-01	287495
1995-01-01	295347
1995-04-01	301401
1995-07-01	309466
1995-10-01	317118
1996-01-01	327744
1996-04-01	342321
1996-07-01	360840
1996-10-01	382754
1997-01-01	401006
1997-04-01	432163
1997-07-01	452574
1997-10-01	450162
1998-01-01	461059
1998-04-01	483820
1998-07-01	492858
1998-10-01	473574
1999-01-01	468331
1999-04-01	481847
1999-07-01	489060
1999-10-01	496821
2000-01-01	513175
2000-04-01	516019
2000-07-01	543484
2000-10-01	540500
2001-01-01	542617
2001-04-01	537710
2001-07-01	543074
2001-10-01	536289
2002-01-01	539197
2002-04-01	556958
2002-07-01	557694
2002-10-01	567589
2003-01-01	573585
2003-04-01	582878
2003-07-01	595469
2003-10-01	612819
2004-01-01	626673
2004-04-01	633390
2004-07-01	641988
2004-10-01	672406
2005-01-01	686074
2005-04-01	666541
2005-07-01	673328
2005-10-01	690140
2006-01-01	726278
2006-04-01	725661
2006-07-01	745722
2006-10-01	789684
2007-01-01	816552
2007-04-01	860048
2007-07-01	877400
2007-10-01	902778
2008-01-01	918808
2008-04-01	941605
2008-07-01	920798
2008-10-01	886535
2009-01-01	879778
2009-04-01	916889
2009-07-01	963610
2009-10-01	1000370
2010-01-01	1011283
2010-04-01	1024622
2010-07-01	1086987
2010-10-01	1121980
2011-01-01	1182038
2011-04-01	1226204
2011-07-01	1223387
2011-10-01	1250802
2012-01-01	1302782
2012-04-01	1333317
2012-07-01	1404552
2012-10-01	1475447
2013-01-01	1501071
2013-04-01	1549376
2013-07-01	1609459
2013-10-01	1683570
2014-01-01	1704521
2014-04-01	1762480
2014-07-01	1772086
2014-10-01	1823632
2015-01-01	1827153
2015-04-01	1886694
2015-07-01	1890141
2015-10-01	1877437
2016-01-01	1927577
2016-04-01	1998840
2016-07-01	2030471
2016-10-01	2094171
2017-01-01	2172107
2017-04-01	2257581
2017-07-01	2337526
2017-10-01	2430138
2018-01-01	2517060
2018-04-01	2536085