Year	Percent
1979-01-01	64.3833551750000
1980-01-01	65.1744449750000
1981-01-01	65.3674131333333
1982-01-01	64.1644143916667
1983-01-01	61.9402251750000
1984-01-01	62.8239656666667
1985-01-01	63.7218024833333
1986-01-01	65.1448136250000
1987-01-01	65.3028818416667
1988-01-01	66.4817301083333
1989-01-01	68.1985719416667
1990-01-01	68.3713618583333
1991-01-01	65.9215015750000
1992-01-01	64.9326842833334
1993-01-01	64.6185830416667
1994-01-01	66.0025135500000
1995-01-01	67.6283765000000
1996-01-01	67.6637293000000
1997-01-01	67.3647924750000
1998-01-01	67.8004793833333
1999-01-01	68.2320225083333
2000-01-01	69.0961344333333
2001-01-01	69.0009861916666
2002-01-01	69.3591415000000
2003-01-01	70.0112448833333
2004-01-01	70.2992577833333
2005-01-01	71.5440314166667
2006-01-01	72.1226234000000
2007-01-01	72.8000677416667
2008-01-01	73.2043069000000
2009-01-01	72.0510673833333
2010-01-01	72.3702422000000
2011-01-01	72.6578631750000
2012-01-01	72.3430862583333
2013-01-01	71.9667508250000
2014-01-01	71.5636130750000
2015-01-01	72.1562770000000
2016-01-01	72.4304993250000
2017-01-01	72.9826622333333