Quarter	Percent
1968-01-01	14.8035577065624
1968-04-01	12.1165704410667
1968-07-01	12.6240875021363
1968-10-01	12.4115490153226
1969-01-01	14.6437566008612
1969-04-01	11.9111111111111
1969-07-01	12.0468611847922
1969-10-01	11.9929453262787
1970-01-01	14.2355228440494
1970-04-01	12.6094764470231
1970-07-01	12.5545090426913
1970-10-01	13.4677799535828
1971-01-01	13.5940338806271
1971-04-01	12.0579559836929
1971-07-01	12.5215328757321
1971-10-01	12.7677806341045
1972-01-01	14.3966820327090
1972-04-01	12.0034542314335
1972-07-01	12.9391602399314
1972-10-01	14.5780051150895
1973-01-01	14.3100718548289
1973-04-01	13.1807646169431
1973-07-01	12.7226463104326
1973-10-01	12.4800938186980
1974-01-01	14.0797285835454
1974-04-01	13.6785757560021
1974-07-01	13.0727354555054
1974-10-01	13.1679389312977
1975-01-01	14.7092462892758
1975-04-01	13.3836832545502
1975-07-01	12.9199735031159
1975-10-01	13.0037255969183
1976-01-01	14.1419293627704
1976-04-01	13.0946115288221
1976-07-01	12.9676348101554
1976-10-01	14.1063179530444
1977-01-01	15.8371313875068
1977-04-01	14.3685150152732
1977-07-01	14.7071702244116
1977-10-01	14.5893094168956
1978-01-01	15.9123382004567
1978-04-01	14.0559251510379
1978-07-01	14.5725473627206
1978-10-01	14.1706393921008
1979-01-01	15.8742081556270
1979-04-01	13.5547748971953
1979-07-01	14.1620713243352
1979-10-01	14.1299521289547
1980-01-01	15.0766537485418
1980-04-01	13.4639826376202
1980-07-01	14.0724149230295
1980-10-01	14.6022573293915
1981-01-01	14.8322672449457
1981-04-01	14.0277221470202
1981-07-01	14.4591720539123
1981-10-01	15.5985227275567
1982-01-01	15.6828330174342
1982-04-01	14.3153501951534
1982-07-01	14.0424814849326
1982-10-01	15.2029455118727
1983-01-01	15.8639135865096
1983-04-01	14.1664540489506
1983-07-01	14.6515731805003
1983-10-01	15.3580234284828
1984-01-01	15.8696065188933
1984-04-01	15.4832521662329
1984-07-01	15.6775971620820
1984-10-01	16.3648926361803
1985-01-01	16.9848534093181
1985-04-01	15.6803901933946
1985-07-01	16.5611222094726
1985-10-01	16.7519685159816
1986-01-01	17.4594689507249
1986-04-01	16.5087801144012
1986-07-01	16.1801609101732
1986-10-01	16.7120108149576
1987-01-01	17.7612350317511
1987-04-01	16.4733996607681
1987-07-01	16.5267681422239
1987-10-01	17.2025123496002
1988-01-01	17.9501581250494
1988-04-01	17.4291987826463
1988-07-01	17.0031150081137
1988-10-01	17.5594949981902
1989-01-01	18.0343578587296
1989-04-01	17.0447328938329
1989-07-01	16.7234855325195
1989-10-01	16.4478538733911
1990-01-01	17.2789338785738
1990-04-01	16.5149957955713
1990-07-01	16.2373659670370
1990-10-01	15.5121383191559
1991-01-01	15.9786180844099
1991-04-01	15.2226844701147
1991-07-01	15.1984810019644
1991-10-01	14.6784970971629
1992-01-01	15.3134638739072
1992-04-01	15.0206518931289
1992-07-01	15.1287873674761
1992-10-01	14.2858030351600
1993-01-01	14.7445753369098
1993-04-01	14.7248049164668
1993-07-01	14.1435591198969
1993-10-01	15.0227125243348
1994-01-01	15.5585707824514
1994-04-01	14.7712708271714
1994-07-01	14.1176528425068
1994-10-01	14.9886990525295
1995-01-01	15.9247490776786
1995-04-01	14.8557906287091
1995-07-01	15.1614637327786
1995-10-01	14.3493761140820
1996-01-01	15.9271680312774
1996-04-01	15.0821769126492
1996-07-01	14.5182387763933
1996-10-01	13.9854969984696
1997-01-01	15.1763277302716
1997-04-01	14.2062240594226
1997-07-01	15.0424227476787
1997-10-01	14.9381135296628
1998-01-01	15.0509822943096
1998-04-01	14.2673148496364
1998-07-01	15.1052668638220
1998-10-01	14.9519356502055
1999-01-01	14.1243950528769
1999-04-01	14.7252701579385
1999-07-01	15.0503339319532
1999-10-01	15.1364764267990
2000-01-01	15.6911227493946
2000-04-01	16.0149978777567
2000-07-01	15.5894868585732
2000-10-01	15.9692893021807
2001-01-01	16.0023129762262
2001-04-01	16.6166916541729
2001-07-01	16.8229598916689
2001-10-01	16.8701867278535
2002-01-01	16.7776562935377
2002-04-01	16.7895071524807
2002-07-01	17.8127191205116
2002-10-01	16.9699576283726
2003-01-01	17.1679465219018
2003-04-01	16.9315526678075
2003-07-01	17.0384746859132
2003-10-01	16.5764071976095
2004-01-01	17.4830279660025
2004-04-01	17.3728232161096
2004-07-01	17.0898021435883
2004-10-01	17.1541678605476
2005-01-01	17.2071611763741
2005-04-01	16.9049840273655
2005-07-01	16.4846099862296
2005-10-01	17.0842222971935
2006-01-01	16.6249926323368
2006-04-01	15.6656920997202
2006-07-01	16.0649991635907
2006-10-01	16.4134888027169
2007-01-01	15.1644174363443
2007-04-01	15.0269143121446
2007-07-01	15.0160925039139
2007-10-01	15.0518962167666
2008-01-01	14.9195797587162
2008-04-01	14.7869674185464
2008-07-01	15.0231296611379
2008-10-01	14.6404322136988
2009-01-01	15.1264464888858
2009-04-01	15.2480762875891
2009-07-01	15.4823295642712
2009-10-01	15.6273753765120
2010-01-01	15.6047695479079
2010-04-01	15.6069796609346
2010-07-01	16.0479048929753
2010-10-01	16.1870671035972
2011-01-01	16.0567650870494
2011-04-01	15.4756767875481
2011-07-01	16.8876892609429
2011-10-01	16.4391762452107
2012-01-01	16.9441970976247
2012-04-01	17.1886696256726
2012-07-01	17.4298503603424
2012-10-01	16.7977050672656
2013-01-01	16.5457202209332
2013-04-01	16.7105260389726
2013-07-01	16.3516441561384
2013-10-01	16.0311766875740
2014-01-01	15.3328000252789
2014-04-01	15.4056097658784
2014-07-01	14.8311834622541
2014-10-01	14.9191283072290
2015-01-01	14.3795460973204
2015-04-01	14.8048641110917
2015-07-01	13.6970271007843
2015-10-01	14.2858274438306
2016-01-01	14.0121509264549
2016-04-01	13.5296230811522
2016-07-01	12.9445785414977
2016-10-01	13.3507970926899
2017-01-01	12.9983010386255
2017-04-01	12.7497209041610
2017-07-01	11.8776575426751
2017-10-01	11.7235345581802
2018-01-01	11.9503206876585
2018-04-01	11.1795172481188
2018-07-01	11.6454092061156