Year	Percent
1973-01-01	8.576989999999999
1974-01-01	9.670320000000000
1975-01-01	8.398740000000000
1976-01-01	8.168280000000001
1977-01-01	9.931010000000000
1978-01-01	14.314500000000000
1979-01-01	14.174000000000001
1980-01-01	15.814500000000000
1981-01-01	15.871700000000000
1982-01-01	15.473900000000000
1983-01-01	16.305999999999997
1984-01-01	20.595400000000000
1985-01-01	18.989600000000000
1986-01-01	17.981200000000000
1987-01-01	12.145800000000000
1988-01-01	11.689200000000000
1989-01-01	11.451700000000000
1990-01-01	11.243800000000000
1991-01-01	10.342400000000000
1992-01-01	9.480080000000001
1993-01-01	9.433200000000000
1994-01-01	9.735720000000000
1995-01-01	10.256500000000000
1996-01-01	11.267000000000001
1997-01-01	13.138900000000000
1998-01-01	14.454600000000000
1999-01-01	15.396100000000000
2000-01-01	17.065200000000000
2001-01-01	18.473600000000000
2002-01-01	19.582000000000000
2003-01-01	16.114800000000000
2004-01-01	15.116600000000000
2005-01-01	17.585800000000000
2006-01-01	21.755400000000000
2007-01-01	24.527200000000000
2008-01-01	26.782300000000000
2009-01-01	29.874700000000000
2010-01-01	33.470000000000000
2011-01-01	39.317900000000000
2012-01-01	39.737900000000000
2013-01-01	39.816700000000000
2014-01-01	40.152500000000000