Quarter	Percent
1968-01-01	60.1213014194312
1968-04-01	52.6535308499928
1968-07-01	51.7439200116613
1968-10-01	55.2765788211625
1969-01-01	58.8892331111188
1969-04-01	52.2128236368545
1969-07-01	53.0251785928560
1969-10-01	56.3935885369929
1970-01-01	59.3214189836881
1970-04-01	52.8795663612126
1970-07-01	53.0883804926435
1970-10-01	57.0739862637032
1971-01-01	60.0195939812995
1971-04-01	52.6436250488264
1971-07-01	52.7333704242120
1971-10-01	54.9231262945999
1972-01-01	60.8081489445969
1972-04-01	54.5595279146685
1972-07-01	54.0792179620813
1972-10-01	56.0955073538500
1973-01-01	58.4471590492986
1973-04-01	54.7779850132036
1973-07-01	54.0575243965074
1973-10-01	54.5751896355370
1974-01-01	59.1578947368421
1974-04-01	54.2717086834734
1974-07-01	54.6080918854501
1974-10-01	57.0798806876573
1975-01-01	60.0303170846193
1975-04-01	54.3729978995722
1975-07-01	53.7664488079271
1975-10-01	57.2733124721445
1976-01-01	59.8256203890007
1976-04-01	54.3280106453759
1976-07-01	53.0510234195493
1976-10-01	56.1992721011232
1977-01-01	59.8855807086614
1977-04-01	53.9023158300845
1977-07-01	52.9382233823465
1977-10-01	55.0403983351960
1978-01-01	58.6373126156162
1978-04-01	52.5369097064395
1978-07-01	52.3641459716111
1978-10-01	54.6699847547305
1979-01-01	57.9985094891678
1979-04-01	52.5061363962054
1979-07-01	52.2780237044515
1979-10-01	54.9210895837987
1980-01-01	58.1408296345005
1980-04-01	51.9211657700866
1980-07-01	51.8775050142267
1980-10-01	55.9727568573121
1981-01-01	59.0528922279884
1981-04-01	53.1914488327390
1981-07-01	53.0531302229314
1981-10-01	55.3818753035773
1982-01-01	58.0833691699309
1982-04-01	52.4680153080280
1982-07-01	53.4847359132606
1982-10-01	55.4486908326049
1983-01-01	56.6296123134199
1983-04-01	52.2829781404221
1983-07-01	51.8842521697428
1983-10-01	54.2320917783336
1984-01-01	57.9292679559030
1984-04-01	52.8748919743959
1984-07-01	53.3165229271324
1984-10-01	55.2606104035248
1985-01-01	57.5842522897805
1985-04-01	51.9905817902103
1985-07-01	52.8934972439995
1985-10-01	55.7270945678633
1986-01-01	58.4320836625969
1986-04-01	53.9422362555721
1986-07-01	53.3730313291852
1986-10-01	54.9709954678391
1987-01-01	57.8397140782961
1987-04-01	53.6258712569153
1987-07-01	53.4327862385416
1987-10-01	54.3783815452614
1988-01-01	56.9409865722014
1988-04-01	53.4310760987772
1988-07-01	53.1847200556648
1988-10-01	55.0526103319399
1989-01-01	56.4483479236943
1989-04-01	52.7167863826178
1989-07-01	52.5665588423498
1989-10-01	53.7020125147979
1990-01-01	55.6130425547626
1990-04-01	51.1535099748427
1990-07-01	51.0567068532958
1990-10-01	52.9061806336303
1991-01-01	54.1263593380615
1991-04-01	50.0449744746794
1991-07-01	49.2715815012787
1991-10-01	51.8491150900014
1992-01-01	53.0189503205130
1992-04-01	51.1327262846335
1992-07-01	49.9568787660996
1992-10-01	51.4009657405299
1993-01-01	52.8937126623502
1993-04-01	50.1069747539581
1993-07-01	50.0641848523748
1993-10-01	52.0142631278126
1994-01-01	53.4444256034621
1994-04-01	50.5574248504840
1994-07-01	50.8135036244372
1994-10-01	52.5416133162612
1995-01-01	53.1289910600256
1995-04-01	50.0634238720042
1995-07-01	50.2965379497451
1995-10-01	52.1076242752058
1996-01-01	54.0722082283795
1996-04-01	50.2938691733117
1996-07-01	49.7083324879520
1996-10-01	50.9492553732985
1997-01-01	52.7006426392929
1997-04-01	49.8982008143935
1997-07-01	49.1655004444286
1997-10-01	50.2027575020276
1998-01-01	51.8413767611588
1998-04-01	49.3529959792096
1998-07-01	48.6347279629339
1998-10-01	50.4980914521497
1999-01-01	51.7300041913317
1999-04-01	49.1688336463154
1999-07-01	48.7199991068463
1999-10-01	50.3537735849057
2000-01-01	51.6983105901712
2000-04-01	49.7231170554272
2000-07-01	49.3661167055846
2000-10-01	50.3998122546510
2001-01-01	51.4472447310010
2001-04-01	50.5867907686379
2001-07-01	50.4029174205295
2001-10-01	51.1382514771908
2002-01-01	51.6680855894205
2002-04-01	51.1291816275110
2002-07-01	50.1936540027810
2002-10-01	51.2578686115541
2003-01-01	51.2866001451416
2003-04-01	50.6088280276772
2003-07-01	50.0005056998356
2003-10-01	50.2392779179614
2004-01-01	51.1566571035355
2004-04-01	49.5642681766501
2004-07-01	48.9783112963451
2004-10-01	49.6442168280780
2005-01-01	50.2288654356523
2005-04-01	48.9452953761543
2005-07-01	48.1989608202334
2005-10-01	49.3378817754810
2006-01-01	49.7738886110394
2006-04-01	48.3323919592168
2006-07-01	48.0735489651983
2006-10-01	47.8079317155661
2007-01-01	48.6130250958555
2007-04-01	47.5583419508653
2007-07-01	46.7613191912257
2007-10-01	46.7752031227578
2008-01-01	47.9871916278640
2008-04-01	45.8811261730970
2008-07-01	46.1055263132566
2008-10-01	47.0670018037399
2009-01-01	47.1392559184168
2009-04-01	46.1373767013630
2009-07-01	45.6244208292231
2009-10-01	46.5559489787971
2010-01-01	46.5796365308584
2010-04-01	46.1268216161269
2010-07-01	45.2216338465688
2010-10-01	45.8780906739047
2011-01-01	45.8884138656606
2011-04-01	44.9414609496516
2011-07-01	45.6523749004535
2011-10-01	45.7631490189076
2012-01-01	45.8849368152034
2012-04-01	46.1454754259371
2012-07-01	46.1046755794673
2012-10-01	45.4672448721597
2013-01-01	44.4836578349538
2013-04-01	44.9421711357586
2013-07-01	43.9585136995655
2013-10-01	43.2326662496002
2014-01-01	43.5227305950372
2014-04-01	42.2883525473671
2014-07-01	42.2951153531074
2014-10-01	41.8234273948857
2015-01-01	41.2638366457019
2015-04-01	41.2572891486398
2015-07-01	40.0482283829367
2015-10-01	39.9502899904817
2016-01-01	39.4502745114412
2016-04-01	39.6985340994406
2016-07-01	38.2143599102833
2016-10-01	38.3084160843185
2017-01-01	37.5322813455546
2017-04-01	37.1255465471404
2017-07-01	35.7776816042790
2017-10-01	36.0740185046262
2018-01-01	35.0063390481604
2018-04-01	34.8354246533700
2018-07-01	33.5937500000000