Quarter	Percent
1968-01-01	25.3959292054563
1968-04-01	22.7114652034130
1968-07-01	22.9847206608773
1968-10-01	23.6998882290069
1969-01-01	25.6004723882270
1969-04-01	23.0234222525795
1969-07-01	23.3886864382068
1969-10-01	24.0594725246784
1970-01-01	25.6328794782893
1970-04-01	23.1303367984363
1970-07-01	23.6466162942600
1970-10-01	24.4109430383629
1971-01-01	25.6382132976941
1971-04-01	24.1765095212702
1971-07-01	24.4234227478859
1971-10-01	24.7461875503572
1972-01-01	26.0825475151137
1972-04-01	24.4790344762176
1972-07-01	24.2745189423225
1972-10-01	24.3356508345561
1973-01-01	25.0868438934022
1973-04-01	23.8723356187614
1973-07-01	23.9535084685784
1973-10-01	24.0031501909136
1974-01-01	25.5354887642400
1974-04-01	24.1286149680368
1974-07-01	24.6905347898532
1974-10-01	25.0672629246963
1975-01-01	26.5100524625669
1975-04-01	24.6823256525806
1975-07-01	24.5701107918691
1975-10-01	25.0443797885578
1976-01-01	26.0831444069112
1976-04-01	24.5179290363870
1976-07-01	24.2504722574471
1976-10-01	24.5202452784999
1977-01-01	25.5229631580642
1977-04-01	23.5398619247788
1977-07-01	23.6934629227399
1977-10-01	23.8738988690417
1978-01-01	24.7589371040533
1978-04-01	22.8731839950093
1978-07-01	23.1847567714697
1978-10-01	23.2014464667799
1979-01-01	24.1532150701332
1979-04-01	22.5676175320259
1979-07-01	22.6373252743744
1979-10-01	22.6911554984452
1980-01-01	23.8234736019510
1980-04-01	22.4022018199084
1980-07-01	22.4662213717819
1980-10-01	22.5489334307256
1981-01-01	23.5713046669226
1981-04-01	22.1411085867549
1981-07-01	22.4342775483520
1981-10-01	22.1420539669296
1982-01-01	22.7880296943674
1982-04-01	21.6570296872674
1982-07-01	22.0856616005224
1982-10-01	21.6044349837289
1983-01-01	22.0458433429810
1983-04-01	20.9110850410149
1983-07-01	20.8429377448281
1983-10-01	21.1804405684591
1984-01-01	22.0335464537897
1984-04-01	20.6706516084549
1984-07-01	20.6178114423268
1984-10-01	20.6575122960232
1985-01-01	21.6756163879027
1985-04-01	20.4838892213010
1985-07-01	20.5436087126670
1985-10-01	20.8943778536262
1986-01-01	21.4175878025718
1986-04-01	20.2049769020457
1986-07-01	20.2983927718113
1986-10-01	20.7894662983364
1987-01-01	21.3032714814648
1987-04-01	19.9197383347777
1987-07-01	20.0623125743503
1987-10-01	20.2165473276540
1988-01-01	20.6473029082275
1988-04-01	19.4481909906861
1988-07-01	19.5974068208702
1988-10-01	19.8919504554763
1989-01-01	20.1045058849858
1989-04-01	18.7658039799226
1989-07-01	19.1214226842513
1989-10-01	19.1975765463328
1990-01-01	19.2309576426595
1990-04-01	18.4950239449909
1990-07-01	18.8192258605934
1990-10-01	18.7458414539897
1991-01-01	18.8645598620557
1991-04-01	18.1834839730950
1991-07-01	18.4060157812611
1991-10-01	17.9358478291339
1992-01-01	18.5846015652459
1992-04-01	17.9854270578206
1992-07-01	18.4563955807990
1992-10-01	17.7068129457099
1993-01-01	19.0360528819680
1993-04-01	18.0288370644020
1993-07-01	18.4606912399563
1993-10-01	17.9580859351744
1994-01-01	18.9474258017938
1994-04-01	17.9198097251089
1994-07-01	18.5796491227355
1994-10-01	18.5349081077541
1995-01-01	19.0951836010649
1995-04-01	18.1787118409650
1995-07-01	18.2772764291736
1995-10-01	18.4934794218867
1996-01-01	18.7391750480676
1996-04-01	17.8637230946420
1996-07-01	17.9216662214329
1996-10-01	18.0759422686629
1997-01-01	18.0075109784164
1997-04-01	17.3128117661779
1997-07-01	17.5952700688683
1997-10-01	17.7702658536311
1998-01-01	18.0439059851084
1998-04-01	17.5962695559244
1998-07-01	17.7800057898079
1998-10-01	17.9755078936053
1999-01-01	18.4558686785213
1999-04-01	17.7853982029385
1999-07-01	17.7515517898505
1999-10-01	17.8141160973463
2000-01-01	18.5694696054750
2000-04-01	17.6223948109143
2000-07-01	17.8798710246703
2000-10-01	17.7529463725199
2001-01-01	17.9751587043340
2001-04-01	17.6061754650822
2001-07-01	17.8050172510217
2001-10-01	17.6158933254875
2002-01-01	18.2797345170474
2002-04-01	17.9595288335476
2002-07-01	17.8174899732800
2002-10-01	17.4563448088561
2003-01-01	18.2256101512966
2003-04-01	17.5000423093624
2003-07-01	17.6655715962546
2003-10-01	17.4563708131312
2004-01-01	17.9255322683609
2004-04-01	17.5053378540203
2004-07-01	17.4450949461825
2004-10-01	17.6712340452112
2005-01-01	17.8400964703453
2005-04-01	17.1436244339184
2005-07-01	17.2118194377032
2005-10-01	17.3710998231186
2006-01-01	17.5013081283764
2006-04-01	16.8238949796809
2006-07-01	16.9073720826620
2006-10-01	16.9501331082050
2007-01-01	17.2611334517762
2007-04-01	16.2101577458101
2007-07-01	16.6578836477530
2007-10-01	16.3356704934338
2008-01-01	16.8337715708659
2008-04-01	16.3773644978616
2008-07-01	16.4795895626976
2008-10-01	16.2196039711888
2009-01-01	16.4471109133139
2009-04-01	16.2590340175163
2009-07-01	15.8438362209975
2009-10-01	15.9239890894813
2010-01-01	16.1843575228928
2010-04-01	15.7733154333915
2010-07-01	15.6191772323116
2010-10-01	15.8458260765703
2011-01-01	15.8945015550571
2011-04-01	15.3557134237132
2011-07-01	15.6738058106408
2011-10-01	15.8307510594551
2012-01-01	16.3322810636002
2012-04-01	15.5912361679478
2012-07-01	15.9362303043752
2012-10-01	15.8188816262801
2013-01-01	15.6918160763936
2013-04-01	14.9821656966500
2013-07-01	15.1835876400848
2013-10-01	14.7065298110055
2014-01-01	15.1713903136607
2014-04-01	14.6321742353615
2014-07-01	14.7387279405002
2014-10-01	14.3845838666847
2015-01-01	14.6888075407830
2015-04-01	14.5357290361932
2015-07-01	14.3119056765322
2015-10-01	14.1620364405659
2016-01-01	14.2165310328013
2016-04-01	14.0625074441358
2016-07-01	13.6593987960142
2016-10-01	13.5255262415035
2017-01-01	13.8465173356548
2017-04-01	13.4376601337447
2017-07-01	13.2473505830048
2017-10-01	12.8351205719824
2018-01-01	12.9010265887076
2018-04-01	12.6301754511153
2018-07-01	12.3913505474643