Quarter	Percent
1968-01-01	74.6040707945437
1968-04-01	77.2885347965870
1968-07-01	77.0152793391227
1968-10-01	76.3001117709931
1969-01-01	74.3995276117730
1969-04-01	76.9765777474205
1969-07-01	76.6113135617932
1969-10-01	75.9405274753216
1970-01-01	74.3671205217107
1970-04-01	76.8696632015637
1970-07-01	76.3533837057400
1970-10-01	75.5890569616371
1971-01-01	74.3617867023059
1971-04-01	75.8234904787298
1971-07-01	75.5765772521141
1971-10-01	75.2538124496428
1972-01-01	73.9174524848863
1972-04-01	75.5209655237824
1972-07-01	75.7254810576775
1972-10-01	75.6643491654439
1973-01-01	74.9131561065978
1973-04-01	76.1276643812386
1973-07-01	76.0464915314216
1973-10-01	75.9968498090864
1974-01-01	74.4645112357600
1974-04-01	75.8713850319632
1974-07-01	75.3094652101468
1974-10-01	74.9327370753037
1975-01-01	73.4899475374331
1975-04-01	75.3176743474194
1975-07-01	75.4298892081309
1975-10-01	74.9556202114422
1976-01-01	73.9168555930888
1976-04-01	75.4820709636130
1976-07-01	75.7495277425529
1976-10-01	75.4797547215001
1977-01-01	74.4770368419358
1977-04-01	76.4601380752212
1977-07-01	76.3065370772601
1977-10-01	76.1261011309583
1978-01-01	75.2410628959467
1978-04-01	77.1268160049907
1978-07-01	76.8152432285303
1978-10-01	76.7985535332201
1979-01-01	75.8467849298668
1979-04-01	77.4323824679741
1979-07-01	77.3626747256256
1979-10-01	77.3088445015548
1980-01-01	76.1765263980490
1980-04-01	77.5977981800916
1980-07-01	77.5337786282181
1980-10-01	77.4510665692744
1981-01-01	76.4286953330774
1981-04-01	77.8588914132451
1981-07-01	77.5657224516480
1981-10-01	77.8579460330704
1982-01-01	77.2119703056326
1982-04-01	78.3429703127326
1982-07-01	77.9143383994776
1982-10-01	78.3955650162711
1983-01-01	77.9541566570190
1983-04-01	79.0889149589851
1983-07-01	79.1570622551719
1983-10-01	78.8195594315409
1984-01-01	77.9664535462104
1984-04-01	79.3293483915451
1984-07-01	79.3821885576732
1984-10-01	79.3424877039768
1985-01-01	78.3243836120973
1985-04-01	79.5161107786990
1985-07-01	79.4563912873330
1985-10-01	79.1056221463738
1986-01-01	78.5824121974282
1986-04-01	79.7950230979543
1986-07-01	79.7016072281887
1986-10-01	79.2105337016636
1987-01-01	78.6967285185352
1987-04-01	80.0802616652222
1987-07-01	79.9376874256496
1987-10-01	79.7834526723460
1988-01-01	79.3526970917725
1988-04-01	80.5518090093139
1988-07-01	80.4025931791298
1988-10-01	80.1080495445237
1989-01-01	79.8954941150142
1989-04-01	81.2341960200774
1989-07-01	80.8785773157487
1989-10-01	80.8024234536671
1990-01-01	80.7690423573405
1990-04-01	81.5049760550091
1990-07-01	81.1807741394066
1990-10-01	81.2541585460103
1991-01-01	81.1354401379443
1991-04-01	81.8165160269050
1991-07-01	81.5939842187389
1991-10-01	82.0641521708661
1992-01-01	81.4153984347541
1992-04-01	82.0145729421794
1992-07-01	81.5436044192010
1992-10-01	82.2931870542901
1993-01-01	80.9639471180320
1993-04-01	81.9711629355980
1993-07-01	81.5393087600437
1993-10-01	82.0419140648256
1994-01-01	81.0525741982062
1994-04-01	82.0801902748910
1994-07-01	81.4203508772645
1994-10-01	81.4650918922459
1995-01-01	80.9048163989351
1995-04-01	81.8212881590350
1995-07-01	81.7227235708264
1995-10-01	81.5065205781133
1996-01-01	81.2608249519324
1996-04-01	82.1362769053580
1996-07-01	82.0783337785671
1996-10-01	81.9240577313371
1997-01-01	81.9924890215836
1997-04-01	82.6871882338221
1997-07-01	82.4047299311317
1997-10-01	82.2297341463690
1998-01-01	81.9560940148916
1998-04-01	82.4037304440756
1998-07-01	82.2199942101921
1998-10-01	82.0244921063947
1999-01-01	81.5441313214786
1999-04-01	82.2146017970615
1999-07-01	82.2484482101496
1999-10-01	82.1858839026537
2000-01-01	81.4305303945250
2000-04-01	82.3776051890857
2000-07-01	82.1201289753297
2000-10-01	82.2470536274801
2001-01-01	82.0248412956660
2001-04-01	82.3938245349178
2001-07-01	82.1949827489783
2001-10-01	82.3841066745125
2002-01-01	81.7202654829526
2002-04-01	82.0404711664524
2002-07-01	82.1825100267200
2002-10-01	82.5436551911439
2003-01-01	81.7743898487034
2003-04-01	82.4999576906376
2003-07-01	82.3344284037454
2003-10-01	82.5436291868688
2004-01-01	82.0744677316391
2004-04-01	82.4946621459797
2004-07-01	82.5549050538175
2004-10-01	82.3287659547888
2005-01-01	82.1599035296547
2005-04-01	82.8563755660816
2005-07-01	82.7881805622968
2005-10-01	82.6289001768814
2006-01-01	82.4986918716236
2006-04-01	83.1761050203191
2006-07-01	83.0926279173380
2006-10-01	83.0498668917950
2007-01-01	82.7388665482238
2007-04-01	83.7898422541899
2007-07-01	83.3421163522470
2007-10-01	83.6643295065662
2008-01-01	83.1662284291341
2008-04-01	83.6226355021384
2008-07-01	83.5204104373024
2008-10-01	83.7803960288112
2009-01-01	83.5528890866861
2009-04-01	83.7409659824837
2009-07-01	84.1561637790025
2009-10-01	84.0760109105186
2010-01-01	83.8156424771072
2010-04-01	84.2266845666085
2010-07-01	84.3808227676884
2010-10-01	84.1541739234297
2011-01-01	84.1054984449429
2011-04-01	84.6442865762868
2011-07-01	84.3261941893592
2011-10-01	84.1692489405449
2012-01-01	83.6677189363998
2012-04-01	84.4087638320522
2012-07-01	84.0637696956248
2012-10-01	84.1811183737199
2013-01-01	84.3081839236064
2013-04-01	85.0178343033500
2013-07-01	84.8164123599152
2013-10-01	85.2934701889945
2014-01-01	84.8286096863394
2014-04-01	85.3678257646385
2014-07-01	85.2612720594998
2014-10-01	85.6154161333153
2015-01-01	85.3111924592170
2015-04-01	85.4642709638068
2015-07-01	85.6880943234678
2015-10-01	85.8379635594341
2016-01-01	85.7834689671988
2016-04-01	85.9374925558642
2016-07-01	86.3406012039857
2016-10-01	86.4744737584965
2017-01-01	86.1534826643452
2017-04-01	86.5623398662553
2017-07-01	86.7526494169952
2017-10-01	87.1648794280176
2018-01-01	87.0989734112924
2018-04-01	87.3698245488847
2018-07-01	87.6086494525357