Year	Percent
1976-01-01	28.040000000000000
1977-01-01	31.861300000000000
1978-01-01	33.278500000000000
1979-01-01	33.571700000000000
1980-01-01	33.920900000000000
1981-01-01	33.996300000000000
1982-01-01	33.568100000000000
1983-01-01	36.405200000000000
1984-01-01	34.028500000000000
1985-01-01	33.359700000000000
1986-01-01	31.570300000000000
1987-01-01	30.758200000000000
1988-01-01	27.373400000000000
1989-01-01	27.344200000000000
1990-01-01	30.014000000000000
1991-01-01	31.243000000000002
1992-01-01	33.796200000000000
1993-01-01	46.706700000000000
1994-01-01	56.561300000000000
1995-01-01	58.795200000000000
1996-01-01	59.140000000000000
1997-01-01	59.864100000000000
1998-01-01	54.892100000000000
1999-01-01	50.733800000000000
2000-01-01	55.025000000000000
2001-01-01	57.893700000000000
2002-01-01	60.812900000000000
2003-01-01	62.443999999999996
2004-01-01	65.226600000000000
2005-01-01	69.168000000000000
2006-01-01	72.611700000000000
2007-01-01	73.810900000000000
2008-01-01	74.166400000000000
2009-01-01	75.988500000000000
2010-01-01	78.203200000000000
2011-01-01	77.634700000000000
2012-01-01	79.524100000000000
2013-01-01	84.292600000000000
2014-01-01	91.635000000000000
2015-01-01	95.808600000000000
2016-01-01	98.847100000000000