Year	Percent
1979-01-01	50.6094210166667
1980-01-01	52.0202671666667
1981-01-01	52.1225772750000
1982-01-01	52.1001858166667
1983-01-01	52.2181834666667
1984-01-01	53.0769163500000
1985-01-01	54.3426090583333
1986-01-01	56.8216737583333
1987-01-01	57.6657861416667
1988-01-01	58.8631193333333
1989-01-01	60.5865721333333
1990-01-01	61.8475716916667
1991-01-01	61.6428244833333
1992-01-01	61.7697821916667
1993-01-01	61.6421111666667
1994-01-01	62.7740459083333
1995-01-01	64.0175339583333
1996-01-01	64.2936735166667
1997-01-01	64.0526006833333
1998-01-01	64.1426766500000
1999-01-01	64.1625697583333
2000-01-01	65.2573280500000
2001-01-01	65.9365611000000
2002-01-01	66.1545866500000
2003-01-01	67.0217745250000
2004-01-01	66.7357623000000
2005-01-01	68.1888671250000
2006-01-01	68.8694159666667
2007-01-01	69.4227403083334
2008-01-01	69.9547222750000
2009-01-01	70.1486470916667
2010-01-01	69.9701265333334
2011-01-01	70.4535344750000
2012-01-01	70.3933735166667
2013-01-01	70.4547905000000
2014-01-01	70.5468262083333
2015-01-01	71.2623692083334
2016-01-01	71.6380578166667
2017-01-01	72.3590799166667