Year	Percent
1974-01-01	11.144400000000000
1975-01-01	12.741300000000000
1976-01-01	15.212600000000000
1977-01-01	15.373800000000000
1978-01-01	14.646900000000000
1979-01-01	15.049600000000000
1980-01-01	14.291500000000000
1981-01-01	13.992500000000000
1982-01-01	12.760100000000000
1983-01-01	13.654400000000000
1984-01-01	14.641600000000000
1985-01-01	16.708000000000000
1986-01-01	17.367400000000000
1987-01-01	16.425200000000000
1988-01-01	19.411300000000000
1989-01-01	20.837100000000000
1990-01-01	20.758900000000000
1991-01-01	20.096400000000000
1992-01-01	20.753100000000000
1993-01-01	20.914500000000000
1994-01-01	19.911500000000000
1995-01-01	17.296400000000000
1996-01-01	16.624200000000000
1997-01-01	17.176600000000000
1998-01-01	18.042700000000000
1999-01-01	18.843900000000000
2000-01-01	18.248800000000000
2001-01-01	16.055500000000000
2002-01-01	16.011700000000000
2003-01-01	16.413200000000000
2004-01-01	16.788600000000000
2005-01-01	16.172700000000000
2006-01-01	17.143400000000000
2007-01-01	19.360100000000000
2008-01-01	20.802600000000000
2009-01-01	22.502700000000000
2010-01-01	24.479800000000000
2011-01-01	24.301100000000000
2012-01-01	23.928700000000000
2013-01-01	24.598100000000000
2014-01-01	24.754000000000000
2015-01-01	24.916999999999998
2016-01-01	27.183500000000000