Quarter	Percent
1960-01-01	16.9083391270840
1960-04-01	13.8871312699015
1960-07-01	14.2915481072194
1960-10-01	14.9408526983802
1961-01-01	16.6230078383701
1961-04-01	14.0200954445333
1961-07-01	14.2495648270314
1961-10-01	15.1786986607819
1962-01-01	17.0080459513693
1962-04-01	14.4175696860309
1962-07-01	15.1227942789285
1962-10-01	16.1652085262721
1963-01-01	18.7428248597610
1963-04-01	15.6691050572151
1963-07-01	16.0688895699418
1963-10-01	16.9458315182716
1964-01-01	19.2784657130467
1964-04-01	16.7719871982470
1964-07-01	17.2981976519378
1964-10-01	17.9366763161199
1965-01-01	19.8639965155255
1965-04-01	17.2656075938383
1965-07-01	17.5399566314357
1965-10-01	18.3754790426276
1966-01-01	19.6317685707811
1966-04-01	17.0798385717449
1966-07-01	17.7471393507419
1966-10-01	18.6394632089803
1967-01-01	20.0561704929582
1967-04-01	17.2962193118091
1967-07-01	17.3048792145717
1967-10-01	18.5416608195233
1968-01-01	19.3534967507048
1968-04-01	16.9138018578307
1968-07-01	17.0391301382101
1968-10-01	17.8323386661721
1969-01-01	19.3766873965758
1969-04-01	16.9932149062377
1969-07-01	17.3461187740084
1969-10-01	18.3406727424371
1970-01-01	19.1853701871916
1970-04-01	17.3422647930394
1970-07-01	17.4647148644567
1970-10-01	18.3674534120605
1971-01-01	18.5712999405115
1971-04-01	16.7372419066134
1971-07-01	17.4037105133183
1971-10-01	18.0125367041112
1972-01-01	18.5774981217476
1972-04-01	16.9554495059260
1972-07-01	17.2445228722039
1972-10-01	18.2583350766441
1973-01-01	18.6269880271143
1973-04-01	17.0857506945150
1973-07-01	17.2275383722611
1973-10-01	17.8838820257384
1974-01-01	18.7137944715315
1974-04-01	17.2824338166258
1974-07-01	17.7206840026010
1974-10-01	18.1846123401174
1975-01-01	19.3545216153333
1975-04-01	18.1254614030628
1975-07-01	18.1446921522261
1975-10-01	18.0845076481254
1976-01-01	19.0607858845550
1976-04-01	18.2398128210673
1976-07-01	18.4606455814226
1976-10-01	18.8516326554693
1977-01-01	19.8258721070928
1977-04-01	18.8104817094904
1977-07-01	18.8336269039192
1977-10-01	19.4116434541275
1978-01-01	20.1143460096352
1978-04-01	18.6278992846515
1978-07-01	19.1914775319477
1978-10-01	19.6386544672360
1979-01-01	20.5831025249678
1979-04-01	18.8802034889533
1979-07-01	19.0656148520031
1979-10-01	19.7481971788276
1980-01-01	20.6915732103164
1980-04-01	19.3749056926083
1980-07-01	19.4974796885556
1980-10-01	19.8772697751799
1981-01-01	20.3049486238646
1981-04-01	19.2005364702493
1981-07-01	19.5878821112745
1981-10-01	20.4034764936587
1982-01-01	20.9859339020442
1982-04-01	19.4093812359409
1982-07-01	19.9847034859141
1982-10-01	20.2556936335041
1983-01-01	20.7724100634259
1983-04-01	19.3869469884522
1983-07-01	19.9698547859903
1983-10-01	20.5824286853778
1984-01-01	21.3842253157643
1984-04-01	20.1286687590968
1984-07-01	20.4654471604985
1984-10-01	21.0015704344093
1985-01-01	21.9212774578665
1985-04-01	20.7941253749522
1985-07-01	21.1482178977871
1985-10-01	21.6888946712715
1986-01-01	22.5339523531893
1986-04-01	21.1574198327111
1986-07-01	21.2662074805194
1986-10-01	22.0098552193109
1987-01-01	22.9850874789805
1987-04-01	21.6637856917206
1987-07-01	21.7578331722325
1987-10-01	22.3882441719129
1988-01-01	23.3036255007053
1988-04-01	21.8547249694547
1988-07-01	22.0913452926796
1988-10-01	22.6814187011184
1989-01-01	23.5701658253913
1989-04-01	22.0193568920600
1989-07-01	22.2049979337508
1989-10-01	22.5824093052117
1990-01-01	23.4856155640055
1990-04-01	21.9552735173426
1990-07-01	22.0654646393581
1990-10-01	22.1475142624287
1991-01-01	22.9081449837826
1991-04-01	21.5652272480271
1991-07-01	21.6621359782268
1991-10-01	21.9661970963150
1992-01-01	22.4445618465122
1992-04-01	21.5581095980966
1992-07-01	21.6351814660563
1992-10-01	21.7356653256005
1993-01-01	22.6644240396090
1993-04-01	21.4769984633469
1993-07-01	21.5639254579366
1993-10-01	21.7484448029141
1994-01-01	22.8348084230917
1994-04-01	21.6866597823688
1994-07-01	21.6671590730131
1994-10-01	22.2956998581098
1995-01-01	23.2320668997025
1995-04-01	22.0553586702919
1995-07-01	21.6463098333116
1995-10-01	22.3032490604490
1996-01-01	23.1950847549213
1996-04-01	21.8670497354801
1996-07-01	21.6019038980501
1996-10-01	22.1610141323379
1997-01-01	22.7274164068197
1997-04-01	21.5204276555225
1997-07-01	21.8993847151287
1997-10-01	22.4979287454338
1998-01-01	23.2207793499436
1998-04-01	22.0470535323383
1998-07-01	22.4284067307911
1998-10-01	22.8083483476127
1999-01-01	23.4407024823038
1999-04-01	22.5787051869210
1999-07-01	22.7614884030661
1999-10-01	23.0592101571904
2000-01-01	23.9900892001908
2000-04-01	23.3005317409005
2000-07-01	23.3575330490655
2000-10-01	23.3260314493953
2001-01-01	24.5231908835416
2001-04-01	23.8318195558463
2001-07-01	24.0639386491904
2001-10-01	24.5312729570128
2002-01-01	25.4918942117717
2002-04-01	24.9021929804186
2002-07-01	24.9085725899609
2002-10-01	25.5369340379395
2003-01-01	26.2342169590128
2003-04-01	25.2390633679471
2003-07-01	25.6783713212211
2003-10-01	26.0881320471123
2004-01-01	26.9610747772558
2004-04-01	26.0324196768856
2004-07-01	26.2159497615497
2004-10-01	26.6842234061746
2005-01-01	27.2556234535432
2005-04-01	26.3281242469060
2005-07-01	26.3195011747593
2005-10-01	26.6316468956185
2006-01-01	27.2780345945217
2006-04-01	26.3742048365513
2006-07-01	26.4886258706884
2006-10-01	26.8329784770217
2007-01-01	27.2398921201474
2007-04-01	26.2515080721654
2007-07-01	26.6085288671390
2007-10-01	27.0090520385800
2008-01-01	27.5426230087219
2008-04-01	26.5712811942722
2008-07-01	27.0555887153211
2008-10-01	27.3750675009882
2009-01-01	28.0064736474316
2009-04-01	27.3557863941690
2009-07-01	27.8043465553060
2009-10-01	28.2848811430810
2010-01-01	28.4994574937078
2010-04-01	27.8012703926177
2010-07-01	28.0193892099764
2010-10-01	28.5235559090718
2011-01-01	28.7933349673014
2011-04-01	28.2596386284299
2011-07-01	28.7197941316254
2011-10-01	28.9725461580167
2012-01-01	29.3554638574870
2012-04-01	28.8611032954120
2012-07-01	29.1345508286543
2012-10-01	29.4579853533748
2013-01-01	29.7510896033653
2013-04-01	29.0505367120682
2013-07-01	29.2581419632712
2013-10-01	29.5840915086366
2014-01-01	29.9259273398998
2014-04-01	29.1109551158068
2014-07-01	29.2804478440350
2014-10-01	29.8191067415959
2015-01-01	29.8731176031852
2015-04-01	29.4688796880379
2015-07-01	29.4623341818401
2015-10-01	29.6980402955983
2016-01-01	30.0429075382252
2016-04-01	29.2446858312015
2016-07-01	29.2951091648237
2016-10-01	29.3916649679958
2017-01-01	29.9161422767894
2017-04-01	29.1941815471119
2017-07-01	29.1130662380855
2017-10-01	29.5258907607154
2018-01-01	29.3802554519733
2018-04-01	28.4967779851685
2018-07-01	28.7091950901787