Year	Percent
1974-01-01	9.375210000000001
1975-01-01	7.899100000000000
1976-01-01	8.404520000000000
1977-01-01	8.808069999999999
1978-01-01	8.743750000000000
1979-01-01	9.420570000000000
1980-01-01	8.349230000000000
1981-01-01	8.838560000000001
1982-01-01	9.071240000000000
1983-01-01	9.931380000000000
1984-01-01	11.783200000000000
1985-01-01	12.981800000000000
1986-01-01	12.981800000000000
1987-01-01	12.981800000000000
1988-01-01	12.981800000000000
1989-01-01	12.981800000000000
1990-01-01	12.981800000000000
1991-01-01	12.981800000000000
1992-01-01	12.981800000000000
1993-01-01	18.573900000000000
1994-01-01	18.465000000000000
1995-01-01	19.426100000000000
1996-01-01	19.618000000000000
1997-01-01	20.198200000000000
1998-01-01	20.153700000000000
1999-01-01	20.782800000000000
2000-01-01	22.647200000000000
2001-01-01	28.508900000000000
2002-01-01	33.980900000000000
2003-01-01	35.384300000000000
2004-01-01	36.762600000000000
2005-01-01	37.991800000000000
2006-01-01	39.166700000000000
2007-01-01	39.823500000000000
2008-01-01	40.705500000000000
2009-01-01	38.745800000000000
2010-01-01	37.496100000000000
2011-01-01	40.154600000000000
2012-01-01	41.785000000000000
2013-01-01	43.782000000000000
2014-01-01	44.907500000000000
2015-01-01	44.896400000000000
2016-01-01	44.582500000000000