Year Percent 1991-01-01 10.5892000000000000 1992-01-01 8.8508300000000000 1993-01-01 8.4091700000000000 1994-01-01 7.8725000000000000 1995-01-01 7.6650000000000000 1996-01-01 6.6000000000000000 1997-01-01 7.4783300000000010 1998-01-01 7.7791700000000000 1999-01-01 7.6683300000000000 2000-01-01 7.8883300000000010 2001-01-01 7.7375000000000000 2002-01-01 6.0283300000000000 2003-01-01 5.9458300000000000 2004-01-01 5.0375000000000000 2005-01-01 4.3700000000000000 2006-01-01 4.8825000000000000 2007-01-01 5.3375000000000000 2008-01-01 5.3525000000000000 2009-01-01 4.8766700000000000 2010-01-01 4.7233300000000010 2011-01-01 4.4475000000000000 2012-01-01 4.4431300000000000 2013-01-01 4.3116699999999994 2014-01-01 4.4508300000000010 2015-01-01 4.6108300000000000 2016-01-01 4.1978400000000000