Quarter	Percent
1986-01-01	18.6180124223602
1986-04-01	18.1276134427753
1986-07-01	18.3424646963500
1986-10-01	18.4335685793188
1987-01-01	18.3072817384674
1987-04-01	17.8788338900698
1987-07-01	17.8244765288382
1987-10-01	17.8743235117258
1988-01-01	18.8898032468018
1988-04-01	18.3276145009697
1988-07-01	18.7002751133913
1988-10-01	18.5182443934572
1989-01-01	19.0297131902971
1989-04-01	19.3275456150677
1989-07-01	19.2110280099721
1989-10-01	19.4138660056864
1990-01-01	19.2840060873976
1990-04-01	19.0421234852856
1990-07-01	19.2950972650922
1990-10-01	18.5980175426086
1991-01-01	18.4988305337019
1991-04-01	18.3684990473502
1991-07-01	18.6705080458155
1991-10-01	19.0938963853737
1992-01-01	18.6934743286490
1992-04-01	18.3991683991684
1992-07-01	19.1150075935386
1992-10-01	18.7405576157121
1993-01-01	19.1530054644809
1993-04-01	18.9378484972120
1993-07-01	19.3083378451543
1993-10-01	18.7205704291672
1994-01-01	18.8206191081099
1994-04-01	18.6377544233072
1994-07-01	19.1594970218398
1994-10-01	18.4598184927002
1995-01-01	18.6695419198850
1995-04-01	18.4289244375081
1995-07-01	18.4923972824329
1995-10-01	18.4756763704132
1996-01-01	18.1058140276980
1996-04-01	17.9163227731573
1996-07-01	17.5954005559768
1996-10-01	17.9620793571070
1997-01-01	18.2317682317682
1997-04-01	18.2502644514965
1997-07-01	17.9658914728682
1997-10-01	18.1986542379159
1998-01-01	18.2416231171227
1998-04-01	18.7634177758695
1998-07-01	18.9715335169881
1998-10-01	18.2267814618062
1999-01-01	18.3363802559415
1999-04-01	18.3191230207065
1999-07-01	18.6579875897311
1999-10-01	17.7013168274774
2000-01-01	17.9004119214926
2000-04-01	18.3878787878788
2000-07-01	17.8285645004850
2000-10-01	17.7172267635483
2001-01-01	17.7499394819656
2001-04-01	18.0110296345676
2001-07-01	18.0023017747895
2001-10-01	16.8830384638609
2002-01-01	16.9705723054703
2002-04-01	17.7739067755887
2002-07-01	17.3767152016298
2002-10-01	17.0893251387314
2003-01-01	17.4835145250401
2003-04-01	18.0014216325080
2003-07-01	17.4865646961554
2003-10-01	17.4235294117647
2004-01-01	17.2353148083011
2004-04-01	17.7472205968403
2004-07-01	17.1990889446943
2004-10-01	16.4231239448099
2005-01-01	16.3791601324273
2005-04-01	16.7672313761894
2005-07-01	15.8989512718002
2005-10-01	15.6361955391194
2006-01-01	15.8831662633944
2006-04-01	15.9531061433251
2006-07-01	15.8677306389575
2006-10-01	16.3669682739663
2007-01-01	15.9218196365299
2007-04-01	16.0068551842331
2007-07-01	16.3992462741963
2007-10-01	15.7525655644242
2008-01-01	16.7786381234343
2008-04-01	15.7415314545972
2008-07-01	15.5348095861559
2008-10-01	15.1663349445550
2009-01-01	15.9700136301681
2009-04-01	15.7679645816778
2009-07-01	16.3330119661997
2009-10-01	15.8758917449892
2010-01-01	16.0409363338234
2010-04-01	16.3432709170108
2010-07-01	16.3713557882819
2010-10-01	16.3026256224536
2011-01-01	15.7611771363894
2011-04-01	15.8228924542208
2011-07-01	15.8441705945823
2011-10-01	15.5795454545455
2012-01-01	15.4803865832860
2012-04-01	16.1845102505695
2012-07-01	16.3321167883212
2012-10-01	16.6676170382620
2013-01-01	15.8326684144534
2013-04-01	15.9493815196945
2013-07-01	15.1962180326935
2013-10-01	14.8457474007159
2014-01-01	14.6094148303405
2014-04-01	15.1124675031084
2014-07-01	14.4491406029868
2014-10-01	14.4892578672800
2015-01-01	14.2074670243684
2015-04-01	14.5775353445397
2015-07-01	15.4959250429672
2015-10-01	15.0983958987928
2016-01-01	14.5415708182714
2016-04-01	13.7200586605833
2016-07-01	13.3740738737764
2016-10-01	12.5315707453383
2017-01-01	12.7749306000427
2017-04-01	13.2692614028567
2017-07-01	12.6129458388375
2017-10-01	12.6083075145723
2018-01-01	12.5221746843368
2018-04-01	12.5025960539979
2018-07-01	12.3745992346675