Quarter	Millions of US Dollars
1966-01-01	0
1966-04-01	0
1966-07-01	0
1966-10-01	0
1967-01-01	0
1967-04-01	0
1967-07-01	0
1967-10-01	0
1968-01-01	0
1968-04-01	0
1968-07-01	0
1968-10-01	0
1969-01-01	0
1969-04-01	0
1969-07-01	0
1969-10-01	0
1970-01-01	0
1970-04-01	0
1970-07-01	0
1970-10-01	0
1971-01-01	0
1971-04-01	0
1971-07-01	0
1971-10-01	0
1972-01-01	0
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	42
1976-01-01	43
1976-04-01	45
1976-07-01	125
1976-10-01	150
1977-01-01	226
1977-04-01	245
1977-07-01	200
1977-10-01	209
1978-01-01	321
1978-04-01	593
1978-07-01	1055
1978-10-01	1646
1979-01-01	2032
1979-04-01	2364
1979-07-01	2715
1979-10-01	2913
1980-01-01	2843
1980-04-01	3669
1980-07-01	3465
1980-10-01	3894
1981-01-01	3870
1981-04-01	3611
1981-07-01	3822
1981-10-01	3713
1982-01-01	3827
1982-04-01	4045
1982-07-01	4377
1982-10-01	4863
1983-01-01	5443
1983-04-01	5845
1983-07-01	5633
1983-10-01	5260
1984-01-01	5657
1984-04-01	5905
1984-07-01	6641
1984-10-01	11548
1985-01-01	12192
1985-04-01	12219
1985-07-01	14289
1985-10-01	12094
1986-01-01	12681
1986-04-01	14207
1986-07-01	15597
1986-10-01	18379
1987-01-01	22491
1987-04-01	23219
1987-07-01	23956
1987-10-01	25580
1988-01-01	23401
1988-04-01	21900
1988-07-01	22697
1988-10-01	24153
1989-01-01	23585
1989-04-01	24487
1989-07-01	25907
1989-10-01	27211
1990-01-01	28816
1990-04-01	32234
1990-07-01	34618
1990-10-01	37246
1991-01-01	40976
1991-04-01	46519
1991-07-01	61222
1991-10-01	69991
1992-01-01	84875
1992-04-01	109857
1992-07-01	121002
1992-10-01	121462
1993-01-01	107760
1993-04-01	83483
1993-07-01	84204
1993-10-01	74706
1994-01-01	72745
1994-04-01	73488
1994-07-01	76336
1994-10-01	75137
1995-01-01	82496
1995-04-01	89214
1995-07-01	85635
1995-10-01	90249
1996-01-01	89883
1996-04-01	88209
1996-07-01	78830
1996-10-01	87481
1997-01-01	94273
1997-04-01	98040
1997-07-01	91655
1997-10-01	82452
1998-01-01	74632
1998-04-01	69940
1998-07-01	69485
1998-10-01	81649
1999-01-01	82989
1999-04-01	89666
1999-07-01	98403
1999-10-01	101693
2000-01-01	100317
2000-04-01	112546
2000-07-01	122633
2000-10-01	148199
2001-01-01	151996
2001-04-01	146998
2001-07-01	145791
2001-10-01	141306
2002-01-01	138029
2002-04-01	143779
2002-07-01	146697
2002-10-01	149643
2003-01-01	152172
2003-04-01	176129
2003-07-01	168182
2003-10-01	180913
2004-01-01	167975
2004-04-01	158491
2004-07-01	155062
2004-10-01	167189
2005-01-01	167477
2005-04-01	172997
2005-07-01	167785
2005-10-01	177432
2006-01-01	182838
2006-04-01	190227
2006-07-01	186360
2006-10-01	165090
2007-01-01	173810
2007-04-01	176650
2007-07-01	170085
2007-10-01	187145
2008-01-01	201557
2008-04-01	213971
2008-07-01	203375
2008-10-01	197849
2009-01-01	173323
2009-04-01	177584
2009-07-01	169739
2009-10-01	168589
2010-01-01	174017
2010-04-01	180722
2010-07-01	196145
2010-10-01	188141
2011-01-01	196326
2011-04-01	197550
2011-07-01	177659
2011-10-01	169457
2012-01-01	177378
2012-04-01	195208
2012-07-01	212190
2012-10-01	221329
2013-01-01	248915
2013-04-01	276061
2013-07-01	291160
2013-10-01	310918
2014-01-01	294924
2014-04-01	272466
2014-07-01	255604
2014-10-01	229928
2015-01-01	217147
2015-04-01	232632
2015-07-01	239213
2015-10-01	252934
2016-01-01	285831
2016-04-01	293256
2016-07-01	293274
2016-10-01	292875
2017-01-01	288780
2017-04-01	290209
2017-07-01	296281
2017-10-01	279964
2018-01-01	295465
2018-04-01	299876