Quarter	Millions of US Dollars
1972-04-01	0
1972-07-01	0
1972-10-01	0
1973-01-01	0
1973-04-01	0
1973-07-01	0
1973-10-01	0
1974-01-01	0
1974-04-01	0
1974-07-01	0
1974-10-01	0
1975-01-01	0
1975-04-01	0
1975-07-01	0
1975-10-01	0
1976-01-01	0
1976-04-01	0
1976-07-01	0
1976-10-01	0
1977-01-01	0
1977-04-01	0
1977-07-01	0
1977-10-01	0
1978-01-01	0
1978-04-01	18
1978-07-01	44
1978-10-01	44
1979-01-01	44
1979-04-01	50
1979-07-01	26
1979-10-01	26
1980-01-01	24
1980-04-01	4
1980-07-01	4
1980-10-01	57
1981-01-01	82
1981-04-01	79
1981-07-01	79
1981-10-01	25
1982-01-01	63
1982-04-01	97
1982-07-01	97
1982-10-01	98
1983-01-01	141
1983-04-01	238
1983-07-01	333
1983-10-01	366
1984-01-01	305
1984-04-01	164
1984-07-01	154
1984-10-01	363
1985-01-01	372
1985-04-01	443
1985-07-01	525
1985-10-01	359
1986-01-01	361
1986-04-01	382
1986-07-01	248
1986-10-01	191
1987-01-01	691
1987-04-01	1139
1987-07-01	1242
1987-10-01	1478
1988-01-01	1238
1988-04-01	1017
1988-07-01	1248
1988-10-01	1325
1989-01-01	1122
1989-04-01	1330
1989-07-01	1494
1989-10-01	2052
1990-01-01	2027
1990-04-01	1610
1990-07-01	1487
1990-10-01	1024
1991-01-01	1478
1991-04-01	1647
1991-07-01	1616
1991-10-01	3167
1992-01-01	3102
1992-04-01	3559
1992-07-01	5349
1992-10-01	5104
1993-01-01	4851
1993-04-01	4958
1993-07-01	4112
1993-10-01	3601
1994-01-01	4033
1994-04-01	4630
1994-07-01	4671
1994-10-01	4795
1995-01-01	5699
1995-04-01	6904
1995-07-01	7506
1995-10-01	8157
1996-01-01	7430
1996-04-01	7690
1996-07-01	7972
1996-10-01	10980
1997-01-01	10896
1997-04-01	12187
1997-07-01	13105
1997-10-01	12278
1998-01-01	13031
1998-04-01	15046
1998-07-01	15789
1998-10-01	19444
1999-01-01	19046
1999-04-01	18772
1999-07-01	17840
1999-10-01	15532
2000-01-01	16533
2000-04-01	15383
2000-07-01	17974
2000-10-01	19085
2001-01-01	18859
2001-04-01	21186
2001-07-01	19720
2001-10-01	21469
2002-01-01	19288
2002-04-01	19408
2002-07-01	18107
2002-10-01	17939
2003-01-01	19222
2003-04-01	20206
2003-07-01	22181
2003-10-01	21827
2004-01-01	19512
2004-04-01	16702
2004-07-01	16456
2004-10-01	19116
2005-01-01	21535
2005-04-01	24249
2005-07-01	22703
2005-10-01	23010
2006-01-01	26010
2006-04-01	28366
2006-07-01	31897
2006-10-01	32436
2007-01-01	32163
2007-04-01	34477
2007-07-01	34790
2007-10-01	36236
2008-01-01	39859
2008-04-01	40467
2008-07-01	40737
2008-10-01	34442
2009-01-01	34775
2009-04-01	34228
2009-07-01	36329
2009-10-01	36401
2010-01-01	35203
2010-04-01	39211
2010-07-01	42375
2010-10-01	42940
2011-01-01	46863
2011-04-01	51692
2011-07-01	48593
2011-10-01	57376
2012-01-01	55206
2012-04-01	48287
2012-07-01	50654
2012-10-01	39526
2013-01-01	42690
2013-04-01	54965
2013-07-01	67346
2013-10-01	72258
2014-01-01	75408
2014-04-01	67391
2014-07-01	61357
2014-10-01	71042
2015-01-01	77271
2015-04-01	76625
2015-07-01	75572
2015-10-01	73936
2016-01-01	73189
2016-04-01	82359
2016-07-01	82970
2016-10-01	78407
2017-01-01	75467
2017-04-01	70668
2017-07-01	70524
2017-10-01	72714
2018-01-01	84302
2018-04-01	96206