Quarter	Percent
1976-01-01	11.78
1976-04-01	11.76
1976-07-01	11.74
1976-10-01	12.12
1977-01-01	11.99
1977-04-01	12.59
1977-07-01	13.57
1977-10-01	14.04
1978-01-01	14.62
1978-04-01	15.16
1978-07-01	15.38
1978-10-01	15.88
1979-01-01	15.98
1979-04-01	16.04
1979-07-01	16.51
1979-10-01	17.52
1980-01-01	19.20
1980-04-01	20.47
1980-07-01	21.51
1980-10-01	24.25
1981-01-01	26.59
1981-04-01	27.66
1981-07-01	30.45
1981-10-01	31.81
1982-01-01	33.67
1982-04-01	39.59
1982-07-01	47.88
1982-10-01	46.12
1983-01-01	56.16
1983-04-01	58.63
1983-07-01	57.78
1983-10-01	56.44
1984-01-01	53.11
1984-04-01	50.38
1984-07-01	50.60
1984-10-01	47.54
1985-01-01	49.36
1985-04-01	54.92
1985-07-01	60.98
1985-10-01	65.66
1986-01-01	71.79
1986-04-01	76.97
1986-07-01	87.72
1986-10-01	95.33
1987-01-01	96.25
1987-04-01	93.76
1987-07-01	91.02
1987-10-01	104.29
1988-01-01	117.16
1988-04-01	46.76
1988-07-01	39.90
1988-10-01	45.48
1989-01-01	47.30
1989-04-01	51.97
1989-07-01	35.24
1989-10-01	40.11
1990-01-01	47.15
1990-04-01	35.16
1990-07-01	31.11
1990-10-01	29.23
1991-01-01	24.29
1991-04-01	21.79
1991-07-01	21.72
1991-10-01	19.95
1992-01-01	16.60
1992-04-01	16.01
1992-07-01	20.16
1992-10-01	22.76
1993-01-01	21.31
1993-04-01	18.68
1993-07-01	16.18
1993-10-01	14.68
1994-01-01	11.53
1994-04-01	17.18
1994-07-01	16.73
1994-10-01	16.96
1995-01-01	56.82
1995-04-01	46.39
1995-07-01	34.61
1995-10-01	46.54
1996-01-01	39.12
1996-04-01	27.05
1996-07-01	24.92
1996-10-01	26.97
1997-01-01	21.10
1997-04-01	18.78
1997-07-01	17.18
1997-10-01	17.79
1998-01-01	17.37
1998-04-01	17.24
1998-07-01	27.54
1998-10-01	28.56
1999-01-01	22.84
1999-04-01	18.62
1999-07-01	17.94
1999-10-01	15.42
2000-01-01	13.67
2000-04-01	13.53
2000-07-01	13.29
2000-10-01	14.39
2001-01-01	14.08
2001-04-01	9.47
2001-07-01	7.52
2001-10-01	5.81
2002-01-01	5.82
2002-04-01	5.37
2002-07-01	5.17
2002-10-01	5.13
2003-01-01	6.38
2003-04-01	3.91
2003-07-01	3.34
2003-10-01	3.91
2004-01-01	4.19
2004-04-01	4.41
2004-07-01	5.03
2004-10-01	5.84
2005-01-01	6.39
2005-04-01	6.71
2005-07-01	6.71
2005-10-01	5.89
2006-01-01	5.50
2006-04-01	5.08
2006-07-01	4.89
2006-10-01	4.82
2007-01-01	4.92
2007-04-01	5.01
2007-07-01	5.08
2007-10-01	5.13
2008-01-01	5.41
2008-04-01	5.53
2008-07-01	5.99
2008-10-01	6.02
2009-01-01	5.37
2009-04-01	3.95
2009-07-01	3.46
2009-10-01	3.42
2010-01-01	3.40
2010-04-01	3.43
2010-07-01	3.47
2010-10-01	3.28
2011-01-01	3.34
2011-04-01	3.38
2011-07-01	3.33
2011-10-01	3.26
2012-01-01	3.26
2012-04-01	3.24
2012-07-01	3.26
2012-10-01	3.25
2013-01-01	3.18
2013-04-01	2.97
2013-07-01	2.83
2013-10-01	2.64
2014-01-01	2.54
2014-04-01	2.50
2014-07-01	2.28
2014-10-01	2.15
2015-01-01	2.21
2015-04-01	2.23
2015-07-01	2.16
2015-10-01	2.11
2016-01-01	2.40
2016-04-01	2.57
2016-07-01	2.82
2016-10-01	3.28
2017-01-01	3.93
2017-04-01	4.31
2017-07-01	4.51
2017-10-01	4.62
2018-01-01	5.01
2018-04-01	5.10
2018-07-01	5.46