Year	Percent
1975-01-01	5.9322900000000000
1976-01-01	5.7087400000000000
1977-01-01	5.3354500000000000
1978-01-01	5.7657099999999994
1979-01-01	5.9603300000000000
1980-01-01	4.8504500000000000
1981-01-01	5.6996500000000000
1982-01-01	4.8019300000000005
1983-01-01	5.6425000000000000
1984-01-01	5.8937100000000000
1985-01-01	6.4872500000000000
1986-01-01	7.1916199999999995
1987-01-01	7.3001800000000000
1988-01-01	5.0753800000000000
1989-01-01	5.0792500000000000
1990-01-01	6.6479100000000000
1991-01-01	6.1648300000000000
1992-01-01	6.4383800000000000
1993-01-01	6.1887800000000000
1994-01-01	5.1325400000000005
1995-01-01	5.0460800000000000
1996-01-01	5.0171500000000000
1997-01-01	4.8350300000000010
1998-01-01	4.8094199999999990
1999-01-01	4.6553200000000000
2000-01-01	5.5612800000000000
2001-01-01	8.2639500000000000
2002-01-01	6.8119500000000000
2003-01-01	6.9412899999999995
2004-01-01	7.0788500000000000
2005-01-01	7.3612500000000000
2006-01-01	7.9418800000000000
2007-01-01	8.5151300000000010
2008-01-01	7.4527000000000000
2009-01-01	6.7484399999999996
2010-01-01	6.8899000000000000
2011-01-01	7.1582100000000000
2012-01-01	6.6227199999999990
2013-01-01	6.4419900000000005
2014-01-01	7.0882700000000000
2015-01-01	6.8628300000000010
2016-01-01	6.8410300000000000
2017-01-01	6.2739000000000000