Quarter	Percent
1968-01-01	53.3127636149660
1968-04-01	58.1332689180063
1968-07-01	57.2377621737603
1968-10-01	56.0141914061224
1969-01-01	52.9771926764743
1969-04-01	57.2915447579530
1969-07-01	56.5901618594981
1969-10-01	55.6015244938877
1970-01-01	52.6870735744147
1970-04-01	57.2281821051252
1970-07-01	56.3426116030196
1970-10-01	54.5624780790611
1971-01-01	52.2635596713671
1971-04-01	54.8988741958507
1971-07-01	54.6354237539023
1971-10-01	53.7637372307275
1972-01-01	51.3510763606104
1972-04-01	54.1643559029216
1972-07-01	54.3967169744723
1972-10-01	54.4765675269441
1973-01-01	53.0036505320434
1973-04-01	55.0509054586588
1973-07-01	54.9447724339652
1973-10-01	54.8341774878018
1974-01-01	52.0680681070392
1974-04-01	54.4281170543121
1974-07-01	53.5063878059244
1974-10-01	52.6728455335590
1975-01-01	50.3155702399775
1975-04-01	53.5748824014773
1975-07-01	53.6920460808110
1975-10-01	52.4386810222303
1976-01-01	50.9359572791521
1976-04-01	53.6497568719418
1976-07-01	54.2289408197070
1976-10-01	53.3597334768768
1977-01-01	51.9376154783201
1977-04-01	55.5444202374957
1977-07-01	55.4336575083696
1977-10-01	54.8761609907121
1978-01-01	53.3534149298167
1978-04-01	56.7840652261982
1978-07-01	56.2669194064972
1978-10-01	56.2386484556135
1979-01-01	54.6141326941277
1979-04-01	57.2556784816121
1979-07-01	56.8947817226320
1979-10-01	56.9629508167920
1980-01-01	55.1378160650169
1980-04-01	57.7061249002386
1980-07-01	57.4353596859602
1980-10-01	57.1788219236569
1981-01-01	55.2267760356175
1981-04-01	58.0463541382680
1981-07-01	57.6971784175851
1981-10-01	58.4956317422353
1982-01-01	56.9744892752128
1982-04-01	58.8404513928920
1982-07-01	58.3587619358909
1982-10-01	59.1220374902404
1983-01-01	58.3674602878234
1983-04-01	60.3958378482139
1983-07-01	60.4510136648935
1983-10-01	59.9461112005733
1984-01-01	58.4606596602212
1984-04-01	60.9141996714413
1984-07-01	60.9510448182605
1984-10-01	60.9658523933318
1985-01-01	59.3222605912607
1985-04-01	61.4103400401853
1985-07-01	61.3710612312662
1985-10-01	60.8823315905188
1986-01-01	59.9899844316013
1986-04-01	62.0832025033978
1986-07-01	61.6616576957572
1986-10-01	61.0928542552877
1987-01-01	60.1857486930019
1987-04-01	62.7359229856014
1987-07-01	62.0831654177642
1987-10-01	61.9773920021206
1988-01-01	61.2324704514681
1988-04-01	63.4808937625475
1988-07-01	62.9402622318265
1988-10-01	62.5619696288892
1989-01-01	62.1853863670468
1989-04-01	64.4964765118509
1989-07-01	63.8496886801086
1989-10-01	63.9712130461121
1990-01-01	63.9137197909657
1990-04-01	65.1565991679314
1990-07-01	64.5482575032564
1990-10-01	64.6329252686779
1991-01-01	64.4782754266622
1991-04-01	65.6559730529846
1991-07-01	65.3619851624456
1991-10-01	65.9529423536264
1992-01-01	64.6815266544695
1992-04-01	65.9966546950827
1992-07-01	65.2838369220564
1992-10-01	66.4361265128012
1993-01-01	64.1516848557561
1993-04-01	65.7987215590817
1993-07-01	65.1315457843835
1993-10-01	65.9594880248578
1994-01-01	64.4760571878071
1994-04-01	66.4973831597374
1994-07-01	65.0981396196787
1994-10-01	65.2548464408203
1995-01-01	64.5386063554445
1995-04-01	66.0426771827320
1995-07-01	65.3957659108796
1995-10-01	65.1902118837640
1996-01-01	65.0299341165148
1996-04-01	66.3087084874831
1996-07-01	65.9896814249848
1996-10-01	65.9510536895789
1997-01-01	66.0532799048678
1997-04-01	67.2583626975485
1997-07-01	66.9180982225123
1997-10-01	66.7627954145952
1998-01-01	66.3106880912874
1998-04-01	67.1056499233368
1998-07-01	66.8334968469594
1998-10-01	66.5403343312201
1999-01-01	65.7521103677142
1999-04-01	66.9052450796925
1999-07-01	66.8626441085714
1999-10-01	66.6413568484490
2000-01-01	65.5357873103006
2000-04-01	67.3277018255822
2000-07-01	66.6833495341541
2000-10-01	66.7618117213391
2001-01-01	66.9147375923303
2001-04-01	67.5473881402937
2001-07-01	67.1026978429917
2001-10-01	67.7351456414866
2002-01-01	66.8202109912588
2002-04-01	67.3390618892672
2002-07-01	67.3782461776580
2002-10-01	68.1594366086403
2003-01-01	66.9311955102150
2003-04-01	68.3324684747327
2003-07-01	67.8503368751333
2003-10-01	68.1676924977493
2004-01-01	67.6186625350686
2004-04-01	68.3467507960386
2004-07-01	68.5982990823074
2004-10-01	68.1476776642148
2005-01-01	67.9556477476620
2005-04-01	69.3301955188505
2005-07-01	69.2308755876143
2005-10-01	68.8677996692986
2006-01-01	68.5056929651200
2006-04-01	69.7797244556786
2006-07-01	69.8006736326283
2006-10-01	69.5503248849109
2007-01-01	69.0396993234543
2007-04-01	70.8509642226197
2007-07-01	70.0610858041351
2007-10-01	70.7172672421816
2008-01-01	69.7575633645411
2008-04-01	70.6547785074004
2008-07-01	70.5709420870029
2008-10-01	71.1193372403406
2009-01-01	70.7473978754106
2009-04-01	71.0706283607234
2009-07-01	71.8864803888335
2009-10-01	71.7658901649010
2010-01-01	71.0997696207834
2010-04-01	71.7731926363764
2010-07-01	72.1737354393496
2010-10-01	71.9079691572466
2011-01-01	71.6181312629260
2011-04-01	72.6375974460030
2011-07-01	72.4278163570872
2011-10-01	72.2257759202706
2012-01-01	71.3938466575465
2012-04-01	72.7655155105572
2012-07-01	72.1679635128762
2012-10-01	72.6001289703238
2013-01-01	72.8744841061680
2013-04-01	73.9343582867466
2013-07-01	73.6405276954264
2013-10-01	74.5295072131458
2014-01-01	73.8303772244116
2014-04-01	74.5235072127236
2014-07-01	74.7977146290734
2014-10-01	75.4980948090985
2015-01-01	74.7692993924829
2015-04-01	75.1791974135715
2015-07-01	75.6248746061934
2015-10-01	75.7665576896412
2016-01-01	75.5851284392662
2016-04-01	76.1771976749572
2016-07-01	76.6470947967754
2016-10-01	76.9798683597771
2017-01-01	76.4803728992221
2017-04-01	77.4905736526196
2017-07-01	77.6381318086479
2017-10-01	78.4003226119744
2018-01-01	78.2854845372028
2018-04-01	78.8770455582164
2018-07-01	79.2777562124388