Year	Percent
1973-01-01	27.823800000000000
1974-01-01	30.811000000000000
1975-01-01	27.821600000000000
1976-01-01	22.454100000000000
1977-01-01	20.677200000000000
1978-01-01	19.197200000000000
1979-01-01	20.646800000000000
1980-01-01	21.672700000000000
1981-01-01	25.879400000000000
1982-01-01	29.897300000000000
1983-01-01	27.435400000000000
1984-01-01	27.823600000000000
1985-01-01	31.079200000000000
1986-01-01	30.404100000000000
1987-01-01	31.168500000000000
1988-01-01	34.098900000000000
1989-01-01	36.015000000000000
1990-01-01	39.757200000000000
1991-01-01	45.247800000000000
1992-01-01	49.472500000000000
1993-01-01	53.182600000000000
1994-01-01	62.476700000000000
1995-01-01	66.183200000000000
1996-01-01	57.495400000000000
1997-01-01	67.964200000000000
1998-01-01	50.667300000000000
1999-01-01	51.558500000000000
2000-01-01	53.420700000000000
2001-01-01	53.780100000000000
2002-01-01	54.254900000000000
2003-01-01	39.219300000000000
2004-01-01	24.183500000000000
2005-01-01	29.925300000000000
2006-01-01	31.488000000000003
2007-01-01	30.845100000000000
2008-01-01	32.763600000000000
2009-01-01	34.746800000000000
2010-01-01	36.610800000000000
2011-01-01	40.655000000000000
2012-01-01	51.735100000000000
2013-01-01	58.624400000000000
2014-01-01	60.873700000000000
2015-01-01	61.451200000000000
2016-01-01	62.063600000000000