Year	Percent
1973-01-01	52.675800000000000
1974-01-01	52.761200000000000
1975-01-01	53.999100000000000
1976-01-01	55.202100000000000
1977-01-01	55.547800000000000
1978-01-01	54.031600000000000
1979-01-01	51.484200000000000
1980-01-01	45.046600000000000
1981-01-01	46.756600000000000
1982-01-01	49.334400000000000
1983-01-01	50.655300000000000
1984-01-01	51.404100000000000
1985-01-01	53.161200000000000
1986-01-01	51.891500000000000
1987-01-01	50.116600000000000
1988-01-01	50.289600000000000
1989-01-01	52.124200000000000
1990-01-01	52.337700000000000
1991-01-01	52.337700000000000
1992-01-01	56.844200000000000
1993-01-01	55.568700000000000
1994-01-01	56.290800000000000
1995-01-01	57.989900000000000
1996-01-01	59.683100000000000
1997-01-01	63.171800000000000
1998-01-01	67.414700000000000
1999-01-01	69.302600000000000
2000-01-01	68.855000000000000
2001-01-01	73.532100000000000
2002-01-01	66.795400000000000
2003-01-01	63.428000000000004
2004-01-01	65.432400000000000
2005-01-01	67.764800000000000
2006-01-01	72.291400000000000
2007-01-01	77.034100000000000
2008-01-01	81.497300000000000
2009-01-01	83.809200000000000
2010-01-01	79.841900000000000
2011-01-01	77.110700000000000
2012-01-01	77.250300000000000
2013-01-01	76.363100000000000
2014-01-01	76.728000000000010
2015-01-01	77.658300000000000
2016-01-01	78.524200000000000