Year	Percent
1976-01-01	3.1559000000000000
1977-01-01	3.2852000000000000
1978-01-01	3.7041100000000000
1979-01-01	3.9360199999999996
1980-01-01	3.6430700000000000
1981-01-01	4.2767500000000000
1982-01-01	4.5792300000000000
1983-01-01	4.3050100000000000
1984-01-01	3.8361500000000000
1985-01-01	3.2201700000000000
1986-01-01	3.8543900000000000
1987-01-01	4.7293500000000000
1988-01-01	4.9303500000000000
1989-01-01	4.4525000000000000
1990-01-01	4.4834700000000000
1991-01-01	4.0118400000000000
1992-01-01	3.4290800000000004
1993-01-01	3.0551800000000000
1994-01-01	4.0219900000000000
1995-01-01	3.7706600000000000
1996-01-01	3.7552800000000004
1997-01-01	3.2994000000000000
1998-01-01	3.2946600000000000
1999-01-01	3.3178600000000000
2000-01-01	3.7067300000000003
2001-01-01	4.2016900000000000
2002-01-01	4.6249199999999995
2003-01-01	4.5541500000000000
2004-01-01	4.5901400000000000
2005-01-01	4.3152900000000000
2006-01-01	4.3924000000000000
2007-01-01	4.4097700000000000
2008-01-01	4.4073000000000000
2009-01-01	4.5207500000000000
2010-01-01	4.6838800000000000
2011-01-01	4.3756200000000000
2012-01-01	5.0299900000000000
2013-01-01	4.9523500000000000
2014-01-01	4.9311300000000005
2015-01-01	4.5679500000000000
2016-01-01	4.3298500000000000
2017-01-01	4.7280900000000000